Well. My 21st was last year and it was on a Monday night.
I worked all day. Luckily, I didn't have classes on Monday but my boyfriend did from 7-9:45pm so my parents met up with me for dinner/drinks.
I LOVE to travel and my boyfriend gave me money a few months before my birthday and told me to book a trip the week after finals (May) to wherever I wanted, and could, with that money. It was my birthday present.
I chose Vegas (I'd never been, wanted to go, seemed an appropriate 21st birthday gift, knew he LOVED Vegas and I found a BARGAIN!)
...He asked me if I was interested in marrying him in Vegas on the night of my birthday.

We talked about it for another week or so and finally decided to do it!
So he's now my DH.

We got married the last night of our trip, May 15.
The next night, I went to a local wing place/bar with my brother and boyfriend/DH and got ID'ed. I work in a bank, which has the same hours as the DMV, so I hadn't gotten my ID renewed yet. The waitress was a witch to me and wouldn't serve me anything on an "expired ID" (even though it says 'Valid for 30 days after expiration' on it)
I said "Fine" and drove home and got my passport, which doesn't expire until 2016. She actually went and got her manager because she couldn't "accept a passport as ID" and her manager told her she was crazy, a passport is a FEDERAL ID and as such even better than a DL and gave me a free drink.
I got evil looks from that waitress for the rest of the night, though!