XCOM: Enemy Unknown can have you standing around for ages. Fortunately, the folks at 2K have cooked up a cheat to help you out: Just dress up as the game's Thin Man character and you'll get a VIP badge when you show off your costume at the show.
That badge will grant you access to play XCOM and Borderlands 2 without waiting, plus you'll be able to duck into the XCOM panel on Saturday. You can see what the Thin Man looks like above, and study some concept art on the official blog post, if you need it.
If you don't want to wear a costume but still want some quality hands-on time with Borderlands 2 (and some Joystiq staffers), be sure to stop by the PAX party tomorrow night. The bar is open there no matter who you're dressed as.