There are a lot, but the ones we plan to hit are:

Bellwether's inaugural show in Chelsea, 6-9pm. It's a group show with 24 of their artists.

The gallery that started the Williamsburg -> Chelsea trend, Foxy Production, has a group show titled "Glad Day", featuring Jane Benson, Sean Dack, David Noonan, and Joshua W.F. Thomson. I've seen some pretty interesting drawings by Thomson at the gallery on previous visits. The server hosting their site is down at the moment, so here is the info:

Foxy Production, 6-8pm
547 West 27 St, FL 6
(between 10 and 11 avenues)
t: 212 239 2758
e: info AT foxyproduction DOT com

White Box has a show of contemporary Greek art which opens tonight, 6-8pm.

You can use Douglas Kelley's (mostly accurate) list to see more. Others of note include a group show at Jeff Bailey and a show curated by Augusto Arbizo that looks great at Artemis Greenberg Van Doren (for the uptown crowd).