I was a little irritated when Apple didn't include a dock for the iPhone 3G. That, the $30 price tag, and general laziness are the reasons I still haven't bought one. I've been able to improvise when I need one, but these DIY instructions on how to make your own cardboard iPhone dock have made my day.
Get your cardstock or thin cardboard, download the provided (free) PDF, and watch the video to make your own too. The other perk besides the whole free thing? The design possibilities are endless — I'm already perusing the pretty cardstock at Paper Source!