Well, mine used to fall asleep standing up leaning his arms over the rail. When I would go to lay him back down, he would wake back up and start all over again. The poster who wrote that she may need help learning to get back down again may be onto something though... they learn to get down from standing AFTER they learn to stand... so, maybe she just isn't comfortable with that part of it yet. Do remember to be LOW KEY whatever you do. You do not want to unintentionally reward her behavior. No eye contact, no lights, nothing to indicate anything other than "it's time for sleep"... Gently help her down to sleep position and walk back out. After a few nights of practice, she should be able to do it on her own and then she will ... (after she realizes you are not coming to play). Just be patient. This too shall pass.
Just be sure that if you haven't already, that you raise the rails (lower the platform) of the crib so she can't fall out. You should remove any bumpers (she can stand on these) and mobiles too... and anything else that she can reach out of the crib and grab onto , for safety reasons. I don't recommend a wind up toy, but if you want to play music in her room I think that's a grand idea. We did that for ours from the time they came home from the hospital... just keep it very soft and soothing... we used a celtic strings CD... like strumming harps.. very quietly...
She'll get past it eventually, and you'll be on to the next challenge.... remember these days... they'll be gone in a flash!