I read an article in an old Dragon quite a while ago on PCs who got sent back to a pre-history era, and ever since then I've always had one in my campaign worlds, though I've never used them as of yet.
Alzrius-- I think I remember that-- something about cavehalflings, and survival being the main point of the campaign...
At present, I'm chewing on a design for an alternate history 16th/17th century "Age of Discovery" campaign, so my pre-history would be, well, pre-history... but apropos to that, I'm thinking of limiting the monster palette to include fewer dinosaur-types, but more Pleistocene-type animals. If the aurochs can last in Europe until the 1670's, why not an Indricothere or two?
Plus, some folks think there's still giant sloths creeping around South America...
