Strike a Light!
I bought a couple of these Light Strike rifles for my son for Christmas 2013 when they were being sold in Home Bargains, but it turned out that they were an end of line item which amazed me because they are one of the best toys we've ever come across. So good that I've bought up any final stock that's appeared reasonably priced on eBay. There are some cool attachments for the rifles, my favourite being an underslung grenade launcher. We had one of these with the first rifle, but I got another for £4 on eBay last week. Only difference was that this new one vibrated and the old one didn't. Mysterious, so I opened the older one up and discovered it indeed had a motor with a small eccentric weight attached. This worked with 5 volts applied so I carefully re-soldered the connections and the tiny surface-mount transistor which drives the motor. Reassembled and connected to the rifle it now vibrates. Result and an easy repair.