Here's a solid deal for a little weekend R&R -- the famous Trainz Simulator on the iPad, which we've written about before, has dropped down to the low price of just 99 cents in the App Store for this weekend only. If you're interested in model trains at all, this is a really amazing app, featuring not only the ability to run virtual trains around any number of environments, but even modify and create your own trainsets right there on the iPad's touchscreen. It's not quite as in-depth as the desktop version of the software, but these Trainz guys take this stuff really seriously, so there are a lot (a lot!)