These took quite a few takes to get correct, but I'm really happy with the results. Have to try a few more. Would prefer slightly less spray (less delay), but then the balloon rubber is more likely to be in the shot.
Strobist: SB600 on camera left and below, gobo'd, on 1/64th power. SB800 on camera right and above, gobo'd on 1/64th. White balloon with clear water. Retouching / correction in Aperture.