Here's a new idea (not practical in my opinion, but neat nonetheless). Instead of sticking a mouse in the laptop bag whenever you travel, use your cell phone as a mouse. According to PC World, companies are currently working on making this happen using Bluetooth Technology.

How does it work? According to the article:

"After communicating a cell phone's field of view through a live camera feed to a computer via Bluetooth, the PC establishes the coordinates of its monitor which it sends to a camera phone. Once the camera phone registers the image on the cell phone and recognizes the display coordinates set by the PC through image processing technology, the computer knows exactly what the phone can see, which sets the stage to scroll a PC.
Users can then move the phone or use a stylus on a touch-screen to scroll a PC or move items. The PC and camera phone work together to continuously reposition a PC monitor's coordinates as the phone moves, allowing the cell phone to scroll a PC from any position in a room.
The researchers have developed the software for the Symbian and Windows Mobile OSes for PDAs (personal digital assistants) and camera phones, the researchers said."

Check out the article here!