Kevin from the Hare Krishna temple serves a vegetarian all-you-can-eat lunch on campus Wednesday from 12:00 to 14:00. There will usually be one vegan option. The "suggested donation" is $3.75, or $6 for all-you-can-eat.
Once upon a time the lunches were Monday, Wednesday, and Friday during the school year, but the administration and some venders in the area raised issue with this. For the past two years they're only on Wednesdays.
Especially during the summer the schedule changes around, so it helps to keep abreast of these changes by asking when you go. That, or just follow the delicious smell. :)