Panic button for cellphone
I would like to see cell phones that have a panic button that could be activated if someone was being attacked. The button would be textured so that it could be identified by feel even if it couldn't be seen. It would have a depress-and-slide mechanism so it couldn't be set off accidentally (and there would be a hefty fine if it were set off "accidentally" more than once). On activation, the phone would sound a loud siren, and 911 would be dialed automatically, with the phone going to loudspeaker mode so the attacker would know that 911 had been called. The GPS in the phone would permit the police to locate the attack. The 911 dispatcher would know that the call was from a phone panic button and would send help even if the person calling could not respond.
This may well exist already as a stand-alone device, but people are far more likely to be able to reach their cell phones quickly. In fact, they're probably walking along talking on their phones already, which is why they didn't notice that someone was sneaking up on them in the first place!
Reward: 1. The satisfaction of knowing that some muggings and rapes had been thwarted. 2. Free phones for my family.