Much sympathy to you, jtrose. I have a 2.5 year old, so I know where you are coming from.
Children's sleep patterns are such that they wake up over the course of the night, period. The only question is what happens then. Do they roll over and go back to sleep? Do they feel the need to use the potty? Do they go right back to sleep after the potty or try for some entertainment? Etc.
A piece of advice from Dr. William Sears that has served us very well so far is that if your child wakes up at night, be "dry as toast". Be there -- be a comfort -- but be BO-RING. No songs, no chat, no discussions, just there.
There could be many reasons why your child woke up and wanted comfort that first time -- bad dreams, a growth spurt, a loud noise, whatever. I think that was the chance to be dry as toast and let her know that you were there but unavailable for anything interesting. Once she found out that interesting stuff happens when she woke up, when she woke up the next night (as, again, all children do, all the time, it's just a matter of what next), she thought "hey, party time."
Everyone has different styles of parenting, and it is important to be consistent within that style. I could never ever ever lock my daughter in her room while she is in hysterics. I am not condemning that way of parenting -- it works and works well for many people. But it would be a drastic departure from what we have done thus far. So, if that fits in your general way of parenting, and feels right, it may well be the best way to go. Dry as toast has worked great for us.
One last thought -- have as active
of a day as possible, as that is the single best thing I have found for getting the kiddo to sleep well. Go to the park, run around the backyard, etc., etc., etc.
Here's the Sears website, with lots of useful stuff:
A few specifics:
Best of luck!!