On July 1-4 in Rosemont, it's the 2011 FIDE Continental America's Amateur Chess Championship. There's only one game on July 4th, so you'll have time to recover for work on Tuesday morning! And this event has a $15,000 guaranteed prize fund!!
I'll be playing in the All American Double Class on July 2-3 at the DoubleTree in Oak Brook. One IM and six masters have already registered. The schedule is a bit unusual in that play doesn't begin until Saturday afternoon, and Round 3 is 9:45 Sunday morning. (If you're not staying at the hotel, you may wish to consider asking for a ½-point bye at registration.). This tournament has a $12,000 based on 250 players; approximately $7,000 of the prize fund is guaranteed! (At least that's the way I read it; please correct me if I'm wrong.)
For info on these and other upcoming events (including summer camps, lectures, simuls, and classes), check out the ICA Tournament Calendar!