Looney Labs makes a card game called Aquarius. I really like the artwork on the cards, but I find the game a little too random and chaotic for my tastes. So I started trying to come up with alternate games that could be played with an Aquarius deck.
In January 2003 I started kicking around the idea of a trick-taking game, vaguely inspired by Xactika (which has multiple suits on each card). I posted the idea to the Aquarius mailing list but didn't get any response. I never actually developed this to the point of being playable, but it's still rattling around in the back of my mind.
In March 2003, after showing my Carcassonne-inspired game to Greg Lam, he came up with an idea for a racing game, also using Icehouse pyramids. I don't know if we could recreate it but I might ask him one of these days.
There are several other games using the Aquarius deck listed on the Aquarius instructions page, but I haven't tried them. Pantopia looks the most promising, but I think it's still an unfinished design awaiting further playtesting.
If you have or know of any other game that use Aquarius cards, send me mail and I'll add a link to it. Actually you'd probably be better off sending a link to Looney Labs so it gets onto their Aquarius page, but if it's particularly cool I may single it out on this page too.
I have invented a few other games that don't use Aquarius cards.