That's hilarous. Whenever we have parties (that always includes kegs) we buy a stash of the famous keg cup. My wife also buys these clear plastic ones for liquor drinks. We always have a bunch left over, then when the next party rolls around my wife always asks, "Hey, what happened to all the drink cups?". I use them for the same thing.
Man, foosball, tank, time to put this together, parties, San Ramon. **jealous** I left The Marina District 3.5 years ago. I miss it every day.