With a floyd rose:
Use the trem to slide up into notes - just press it down a little and pick as you let it up gently - sounds great if done subtley - anyone remember Vinnie Moore - he used to do it a ton. not that he was subtle though
You can make some great noises by just pushing down the bar until all the strings are slack and moving the strings with your left hand
Hook your bar
under one of the strings and let go! wild
tap the bar onto the pickup magnets
Just to look cool - divebomb open strings using your
Left hand
With a crybaby wah:
Plug it in the wrong way (guitar into output, input to amp) with your guitars volume down all the way - slowly increase the volume and listen to the squeal, the pitch of which is controlled by your volume knob!
With a slide:
Select the front pickup and use the slide over the pickup - go back and forth and the pickup will "hear" different ends of the neck
With no gizmos whatsoever:
Try bending 2 different notes at the same time - groovy for steel effects - listen to Jerry Donoghue for the master of this. Damn hard
Pull the B string over the edge of the fretboard!
Hit the guitar body with your fist on the upper bout (actually works better on bass though) while fretting chord/note
Lean into your amp and blow air across the strings to encourage feedback
Fret a chord and tap the back of the neck with the knuckles of your right hand - etherial
Muted strings (with left or right hand) really make those funky/heavy riffs (a la the Theme from Shaft or anything by Extreme) sound funky
Good luck,
Steve