If you are part of the group that is having reception issues with your new iPhone 4, here is a great DIY bumper.
http://www.engadget.com/2010/07/01/iphone-4-gets-a-1-alternative-to-pricey-bumpers/
Instead of purchasing a $30 bumper, you can make one with a $1 Bracelet.
What would be interesting is if you could find an Apple branded bracelet.