I usually play the outro riff from Pantera- Floods. Its a guitar part but sounds cool on bass. A ton of arpeggios with wide intervals and finishes up in a higher octave.
My current band is great, but new to live performance (just had a second show). I am lucky if we even do a sound check these days. Usually the way it plays out is like- ok, my stuff turned on... is yours on? lets go...
