[karamazov]

This is quite similar to Shogi, a Japanese variant of chess where you can put down any of your opponent's captured pieces. From what I know, that game is highly strategic; since all of your potential pieces come directly from your opponent, it's probably less chaotic than this variant.

http://en.wikipedia.org/wiki/Shogi

[gcp]

The two player variant of Bughouse is called Crazyhouse. You can play it on the chess servers (freechess.org, chessclub.com etc).

There are also some chess engines that can do it, including the one in Mac OS X, though I don't know if Apple's GUI offers access to it.