Waking a 6 mo. old from a nap...bad idea?

One of my best friends all through grade school is due to give birth on July 26th. Well today she's having a little get together, kind of her 'last hooray' (her words, not mine) before becoming a mom. It starts here at 2:30 down the street from my house at the local bar & grill. My son is sleeping soundly right now and I don't know what to do! I really want to go to the little party but i'm also scared to wake him. I've found in the past that waking him from a nap makes him very grumpy. Everyone is at work so I can't have anyone come sit w/ him. What should I do?!