The Thought Bottle from Complete Arcane can allow a character to reduce anything with any XP cost to 500xp, once. That is, by spending 500xp now, he can wish to his heart's content and craft items and scrolls and commune with gods and so on and so on... and then get all but 500xp back. He can then DO IT AGAIN and afterwards go back to THE SAME LEVEL (not even costing him another 500xp IIRC). Combining this with rituals of renewal from Savage Species (I think) can allow a character to practically gain just about as much free ECL as he wants, continuously stacking more level on top of what he already has and then gaining back all the XP he lost so that he can do it again and again and again.
I'm still waiting for the errata that goes: "Errata: Thought Bottle no longer exists" I see no real way to balance it. It destroys balance in every concievable situation I can think of. I mean, what NON-broken way can you use such a thing?
By the way, the Hulking Hurler is a fun exersize in math. It's not just the improvised weapon rules that are broken as much as carrying capacity rules, and the fact that HH allows you to use a weapon the size of your medium load. If carrying capacity rules were realistic, then the concept of the HH would be strong, but not unbelievably so. But carrying capacity scales exponentially with strength and size and number of legs and number of limbs and all kinds of things, such that if you min/max your medium load, you can deal trillions of damage (litterally) per iterative attack. On the other hand, all that min/maxing of carrying capacity leaves little for things like... oh... the ability to hit things you target, or the ability to withstand ANY kind of attack... or even the ability to go first in a round. Yeah, whatever the HH hits is pretty much dead, gods included (though any god worth mentioning wouldn't get hit in the first place), small planets included (and planets aren't known for dodging capabilities)... but characters of levels much lower than it can kill an HH rather easily.