What do you guys do to stay # for interviews, and technology in general?

I've found myself at that point 10 years out of college and I'm bombing interviews because I don't remember "the basics", or my knowledge is out of date. I've been working with backend ASP.NET and C# for 5 years now but I can't answer any historical or architectural questions about it. I don't remember the 4 (or 3 or 5?) tenets of OOP. No idea what a black and white tree is. SOLID? Durrr. Task vs thread? Ummm, errr. Describe the layers of TCP/IP? Herp derp... What is your favorite new feature of C#6? Lol I'm still on VS2008...thanks for your time, click. Yes I've looked this stuff up after the fact but by then it is too late.