Acting in Sketch 301/ASW

I haven't seen this question answered, so thought it would be useful to find out:
How do Sketch 301s and Advanced Study Writing classes get their casts for the performance?
Is it a list of people that are interested, Advanced Study Improv students, asked by the teacher, or what?
I'm auditioning to be a Maude actor for the first time this year, and if I don't get it I would love to get some experience performing sketches that I'm not writing myself.
Thanks!
How do Sketch 301s and Advanced Study Writing classes get their casts for the performance?
Is it a list of people that are interested, Advanced Study Improv students, asked by the teacher, or what?
I'm auditioning to be a Maude actor for the first time this year, and if I don't get it I would love to get some experience performing sketches that I'm not writing myself.
Thanks!