I find it very fun to play around with multiple technologies and set them up in cool/odd/amazing ways. My latest little endevour provided me with a wireless music backpack of sorts.
Hardware: iPod Touch, MacBook Pro, Cheapo USB speakers.
Software: InsomniaX 2 (Prevent sleeping, Conserve Battery), iTunes (For playing tunes), Control! Server (Enable remote control of Mac), Control! (iPod/iPhone)(Control Mac remotely) & Remote(iPod/iPhone)(Control iTunes remotely)
After installing all the software enable InsomniaX, iTunes and Control! Server. Once those are launched configure your iPod to access your iTunes library (4-digit code, must be on the same wireless network).
Create an Ad-Hoc network using the MacBook and connect the iPod to it. Now turn up the volume on your Mac (you can use Control! for this), dim the keyboard and display, attach the speakers and (somehow) mount the setup in your bag (My bag has little pockets on the sides with elastics that I popped mine into with the wires running into the inner compartment of the bag where the Mac is).
Launch Remote from your iPod, it will find your iTunes and give you (almost) full control over all aspects of iTunes. Congrats you just turned your iPod into a 200$ remote.
If everything went right you should be able to walk around with the bag and control the music using your iPod/iPhone. This is really cool because it's the geek eqivelent of the 80s boombox and has that certain "Wow" factor to it (especially when shown to friends).
Next up: My adventures of installing Debian on my PowerMac G3s. (Sidenote: Look at that transparent plastic. So awesome.)