Okay - everyone, don't laugh (allright go ahead and laugh 'cause the audience will). Here's the dirt cheap version: a Radio Shack electret (omni-directional, surprisingly good mic for ~$25 US), packed with cotton batting (~ $0.50 US) in a kitchen funnel (~$2.00). This setup was invented in an emergency for recording bird sounds in Costa Rica, but it worked darn well in a subsequent musical emergency.