Alex Vause (Laura Prepon)
Backstory: Piper's ex was introduced to the wonderful world of drug smuggling by her dad's dealer, and eventually brought her then-girlfriend into the mix. She also ratted out her former love in order to get a shorter sentence; when we last left her, she was planning to skip town, but ended up back in Litchfield…because Piper ratted her out.
Place in Litchfield's hierarchy: Alex has her friends — Nicky and Piper, at least at first — but she's not entrenched in any one crew. She does, however, cross Pennsatucky and end up stuck in a dryer, albeit briefly.
Pre-OITNB: After her run on That '70s Show ended in 2006, the erstwhile Donna Pinciotti had bit parts on How I Met Your Mother, Castle, and Medium, as well as a starring role on the short-lived series October Road and Are You There, Chelsea?
Best line: "Rule number one: Don't ever fall in love with a straight girl."