I ordered an arduino board that I have been playing with. There is a device I wanted that runs a couple small motors, has an LCD screen, and buttons to control it. The device is new but costs around 5000 dollars. If I can figure out how to work it, I will be able to make the device for about 200 dollars plus my time. Im getting close. Dorkbot Indy is a group I found in Indy but haven't attended any of their meetings. It's a group of people that get together to help with rasberry pi or arduino.
I got my first one a couple years ago and had fun playing with it. I got the new version 2 a couple weeks ago and am trying to find time to play with it.
I think it is a great tool to learn linux. Also, I like to think of them as little Amazon EC2 Cloud servers where the first version Pi would be roughly equil to Amazon's T-1 Micro Instance, and the newer is roughly equivalent to a T-2 micro. Amazon gives a free year of T-1 Micro, but after that it costs around $12/month. A early version $35 Pi does the same thing for practically no cost/month.
I love setting up linux servers. I put a Pi out at my daughters appt where I have it running as a backup DNS server and also serves to backup some of my files using Linux rsync.
The newer one, I may set up as a Linux mail server like Hillary Clinton has at her house. Everyone seems to be curious about having their own mail server right now.
I did buy a book and go through a tutorial for Assemply and Python programming using the Pi and found it quite interesting and helped me to reserect some programming skills I had when I was younger.
I think they also make pretty good bulletproof surfing stations. What's great is if someone does screw one up, you can completely rebuild the OS with hardly any effort.
The neet thing atout a Raspbury Pi is that it has the same broadcom CPU and setup as many common devices around the home such as DVR players. It is a great inexpensive learning tool that has limitless potential.