jhorlock, this site rarely crashes.
However, your connection to Live Chess (presumably this is what you are referring to) must be solid and consistent to enjoy the chess experience there. Some items you can look at: a) are you using the latest version of a fast browser (Chrome or Firefox) without add-ins, b) are you avoiding streaming audio, indexing, backing up, or any other intensive operations while playing, and c) do you have the minimum number of browser tabs open and avoid switching between tabs while playing?
These (and some other factors) might be involved. Of course, this also assumes that you have a strong connection to your ISP, aren't experiencing retransmission due to low signal strength wireless, and any other hardware related issues.
I'm really annoyed about chess.com crashing and costing me a game which I was clearly winning. I had loads of time left. The other player only had a bishop and I was few moves from checkmate. Then chess.com crashed. It had nothing to do with my computer - I checked I loaded other sites, went to chess.com told server not working. Then two minutes later I check my figures and low and behold I've lost loads of rating because I abandoned the game.