I've always wanted to try some liquid latex. Also, what about some body molds, which would give you a momento of the evening? Then there is my favorite: evening out on the town for dinner, drinks and a surprise trip to a strip joint. You could really get him going by mentioning at dinner that you are not wearing panties under your dress or skirt. If you want to add even more excitement to your night on the town, you could splurge the $50 or so it costs to buy a wearable vibrator operated by a wireless remote control and give your guy the remote.
Unfortunately, my wife and I will be out of town w/ the kids at my in-laws, so our 'freaky' evening will be limited to some rather tame (and unnaturally quiet) sex after everyone goes to sleep. Have fun!