Good grammar develops over time, so relax and put down the red pen. Kids need to make mistakes in writing to move toward correctness. They freeze up if they think you'll pounce on every error. You want your daughters to keep writing, since this is the best way for them to develop strong usage skills.
There have been a lot of video games based on Dungeons Dragons, but in the past they have been almost entirely solo, single-player experiences. Now, with the Internet and advances in graphics, we can finally create an online version of that classic sitting-around-the-kitchen-table Dungeons Dragons experience, without people having to actually go out.