Need some really bright LEDs? We are big fans of these 5mm clear UV / Purple LEDs. These emit UV 'blacklight' in the UVA spectrum so they are great for projects with fluorescent materials referred to as UV/blacklight-reactive or 'glow-in-the dark'. They are bright (350mcd) and have about a 20-degree LED beam. They go easily into a breadboard and come in a pack of ten so you can easily add that extra UV zing to your project.
If you need some help using LEDs, please read our "Introduction to using LEDs" tutorial for any electronics project.