The debate is scheduled on Thursday Feb 21st at UT in Austin, Texas. A Statesman article says that students will be invited as well. I'm a good date. Wink. Wink. Nudge. Nudge. From CBS News:
No public tickets will be available to the presidential debate between Hillary Clinton and Barack Obama on the University of Texas campus Feb. 21.
The Obama and Clinton campaign will distribute the tickets by invitation only.