an ebow technique that *I* have found to be fun is to place the ebow on the fretboard with your right hand- let's say around the 5th fret of the 3rd string. Then, in the left hand, hold a slide around the 12th fret of the same string, and start moving up and down the fretboard. All sorts of crazy overtones pop out, and you can switch strings, etc...
Another cool effect: lay the guitar flat on a table, with the ebow sitting on the strings down near the pickups. Place a brass slide somewhere up the fretboard, just laying on the strings; let 'er rip. The vibrating strings will get the slide rocking back and forth (brass slides are never perfectly formed; they tend to be lopsided. With the 'heavy' side down, it'll stay in one place, but rock back and forth slowly), giving a cool tremelo effect. Toy with the volume levels, and you can get the whole guitar vibrating with low-level feedback, which just adds to the motion of the slide.
I once saw a guy in Minneapolis ("Lost in Translation") do this on stage; he set it up, then let it play itself for a loooong time. Really cool sounds, esp. when delayed; sounded like a very minimal Rapoon.