Wait a minute, I thought batgirl wears pants?
You know this is a day before Old Rag. It would be tough to do both... well, for me at least.
One of the old pre-Crisis Barbara Gordon costumes has a yellow skirt. But I'm pretty sure she's talking about one of the easily bought Batgirl costumes at halloween stores which includes a little black skirt.
Would be cool to see this, though:

That's the new Batgirl, btw. Cassandra Cain. Also a very cool character.
And.. y'know.. a jam is a jam, not an intense trainng session.