Here's the mobile guitar rig I use when I want to play in the park right next to our house.
UE Boom guitar amp - Nowadays you can't enter an electronic store without seeing a plethora of Bluetooth speakers. Last month I was invited to a presentation of the UE Boom from Ultimate Ears, the speakers sounds really great especially seeing the relatively small size. I wondered how it would sound to plug a guitar in one and see if it can be used as a guitar amp.
UE Boom guitar amp video
Unpacking the UE Boom
If you are familiar with the Apple unpacking experience, you won't be disappointed with the UE Boom one.