what should i expect from a band showcase?

Usually aboyut 45 minutes, and expect to sit in a room with a lot of other brides and grooms, and a lot of sales people to come up to you with prices and asking you for aaaalll of your contact info. Expect to hear standard wedding fare, usually done in one big huge melody!

Then expect phone calls up the waaazoo until you tell them to buzz off or hire them!