In addition to the IMDb links I usually provide for actor/actress names, I'm going to start trying to more regularly provide wiki links for character names whenever available. Hopefully that will help jar the memory whenever pictures fail to do the trick.
Heroes - "I Am Sylar"
Clint Howard guest starred as 'Tom Miller,' the guy that could shatter glass. He has an amazingly long listing on IMDb.com, and he's quite recognizable even if you may not be able to remember anything in particular that he's been in. I definitely remember him as 'Johnson' in all 3 Austin Powers movies, and not so long ago, he was 'Creepy Rodney' on My Name Is Earl. Thanks to @JamesProps (the Heroes props master), below are some really great shots of Clint from this past Monday's episode.
[scrubs] - "My Cuz"
Elizabeth Banks guest starred as 'Kim' the mother of J.D.'s son Sam. Since the last time she guest starred on [scrubs] she has starred in Role Models, Zach And Miri Make A Porno, & The Uninvited, created a MySpace page (http://myspace.com/elizabethbanks), and joined Twitter (@ElizabethBanks).
Better Off Ted - "Goodbye, Mr. Chips"
Patricia Belcher guest starred as 'Janet' the HR rep. She frequently guest stars on Bones as 'Caroline Julian' a prosecutor in the US Attorney General's office. (I searched around for a little bit, but I couldn't find any pictures of her that I liked that really show the stern characters she portrays.)
Criminal Minds - "A Shade Of Gray"
John Billingsley guest starred as sex offender 'Hugh Rollins.' He previously starred on True Blood as 'Mike Spencer' the coroner and also guest starred in season 1 of Prison Break as 'Terrence Steadman.'
Dollhouse - "Haunted"
Jordan Bridges guest starred as 'Nicolas Bashford' the son of the deceased friend of Adelle. Previously, he starred on Dawson's Creek as 'Oliver Chirchick' but more recently he was on Bionic Woman as 'Tom Hastings.'