Plot ideas, pick your favorite.

[Illirion]

I liked both the race AND the underwater campaign.

The race should be cool, but there should be other objectives (like requiring a special set of items that can be found only at certain locations before you can finish) set by the organisation since it would be too easy to just take the shortest route around the world. Would there be television (or something similar) by then? Then the PC's would also be rewarded by fame if they do well in the race and atract attention from the media. It would be cool to have a lot of people cheering them on when you reach an unknown city for the first time .

Underwater would be cool since there are a lot of cool encounter options in the monster manual and such which you can normally never use in a normal campaign (unless you have the pc's get their boat eaten by a kraken in the middle of the ocean).

Don't really like the toy soldiers since being nerfed or the duration of at least 7 levels seems really anoying in the long run to me.

 

[Sejs]

LostSoul really summed up my feelings on the Great Race.

Pulp it up to the gills and it could be friggin' amazing.

"Dr. Jones. Again we see there is nothing you can possess which I cannot take away..."

 

[crazy_cat]

Great race sounds fun.

 

[Aeric]

The Toy Soldiers could be interesting for a one-shot, but I don't see it lasting longer than that.

The Great Race sounds exciting--it's different, has a focus, but is still open enough to allow all sorts of adventures.

The underwater campaign could very easily just be D&D underwater. Good for a bit of variation, but ultimately a dungeon is a dungeon, even if it is a sea cave.

I voted for #2.

 

[Ambrus]

The toy soldiers' campaign could be fun, but you'd need players that are into it.

I like the Amazing Race idea, though I'd be tempted to turn it into a scavenger hunt as well. It'd help give the PCs things to do in all these exotic locales as well as give them a reason to stop and smell the roses (while they search for the famed blue rose of Machu Pichu!) It'd also give them a better opportunity to explore, interact with locals and directly confront the other racers who are scrambling to find the various objects off the list. When it's all said and done they could discover that the person sponsoring the race has some nefarious purpose in mind for all the items they've collected. Foiling him could be the grand finale to the campaign!

 

[awayfarer]

#1 could be good but I feel like you'd need to be very up front about it. It would probably be better as an adventure in a bigger campaign. Theres only so much mileage you can get out of a nutcracker.

I don't really see how the big race thing could be possible. If it's a race than your players are going to need to stay on their vehicle pretty much at all times. Even if they're frequently being boarded or encountering odd, avian races, they're still in the same setting.

Do you have the Monster Manual 3? I read the entry for the Siege Crab and I was thinking that you could make a nifty 20,000 Leagues Under the Sea type adventure with one of them. The maximum space in one is 20x10x10 so the crew would need to be small, possibly only gnomes halflings and dwarves or other short races. I just think it would nifty to travel under the sea in a giant crab. Actually I could see that being more like Star Trek, visit new places, see new people, etc.

"These are the voyages of the Siege Crab Auntyprice....."

 

[Vyvyan Basterd]

I think the Toy Soldiers idea would work better than people are giving it credit. It doesn't sound like you intend to change the player's abilities, so they feel no direct ill effect. But they can end up facing a Kaiju Squirrel and other such scaled-up creatures. And the yard of the wizard can become a forest/plains/lake/desert/etc. all rolled into one. I would have a lot of fun as player or DM with this idea. <My vote>

Great Race I'm having trouble seeing. It definately doesn't match the genre I am used to. I would try it as a player, but wouldn't expect much from it. I think the variety of locales could suffer.

Under the Sea. Meh. Again, I think too much of the same setting could become boring. I would rather have a portion of a bigger campaign go under the sea, not be stuck there for a whole campaign.

 

[Stormborn]

#1 sounds a lot like a GURPS mini-campaign, and would likely work better as such. Can't see playing it for more than a session or two though.

#2 would be my first choice, but then I love a)airships and b) steampunk and c) Etherscope. In fact, I love the idea so much I want to flame Menexenus for not getting it. But oh well, he defused the idea alread (just kidding Menexenus, not all games are for everyone and if you are unfamiliar with the source material you just wouldn't get it.)

#3 is interesting, something I would like to try sometime. You should check out the new Aquaman: Sword of Atlantis comic to see get some ideas if you decide to go with it.

#4 - Might as well throw out a campaign idea, since you seem to be willing to think about odd stuff: Each player, and the DM, creates 3 or 4 1st (or 3rd or 6th or whatever) level PCs- all of whom are answering a call for mercenaries. The patron is holding a series of contests to determine which agents he hires. Run them through a few challanges and combats set in faux dungeons and arenas where they can battle captured monsters and each other and maybe a few party role specific trials. When a number of PCs equal to the number of players have been chosen put them in a pool and determine some random way of alocating the PCs. Players may wind up with PCs they didn't create this way, but its an experiment. The patron then gives them their mission, to find a piece of Mysterious McGuffin of Many Parts stolen from his ancestor long ago by rebelious servants who scattered the pieces across the globe. IF they have fun, and are succesful, retrieving the first piece then you can go on to the second, with PCs from the pool replacing fallen PCs as needed.

 

[JRRNeiklot]

I like the toy soldiers idea, as long as the dm runs it right. For instance, if a human is chasing them, and one of the soldiers stabs him in the foot with a big sewing needle, he shouldn't just take 2 points of damage and stomp the little bastard. He should howl and hop on one foot long enough for the party to scuttle away and hide. Perhaps into a mouse hole where a more appropriate challenge lies....

 

[Nellisir]

I like #1, assuming you don't pull a bait-n-switch and nerf the PCs. But playing a kickass wooden soldier and fighting a CR 12 Dire Squirrel of Evil? Fun.