Chapel -
THe difficulty with the domain nam 20ies, is the spelling of the term. There are several ways to accomodate this, Twenties (being the most popular) and 20s. The real question is, how much natural traffic is happening, when people type that in, if any?
Development is great, but the problem with developing a domain like this, is your going to have some traffic blead going to the other domains. People are not going to recall the exact spelling, and type in 20s or twenties. With a lot of branding, you could make something of it, but I do believe it will be difficult.
At this time, without any development or branding, the domain probably wont find anything in resale, my guess is this one is a reg fee domain.
Best of luck.
Justin