Explore The Fallen Gate
The Fallen Gate is by far one of the best zones to spend your 20s in. With plenty of heroic mobs, and tons of named mobs, you'll want to grab a group and head in for hours (if not days) of gaming fun.
The Fallen Gate is the former first gate of Neriak, the outer lying area before entering the dark city. For some unknown reason (or at least unknown to me) when the halflings known as the Leatherfoot Brigade, attacked the dark elves (having taken advantage of the distraction of the war that was ensuing outside), the tunnels that lead into the city collapsed. This left us with only access to Neriaks' outer areas, now known as the "Fallen Gate".