There are certain actors who resemble each other, and I find myself wishing that more film directors would cast these actors together so that 'families' in movies would look convincingly related. Here are a bunch I'd recommend:
Daughter: Leelee Sobieski
Mom: Helen Hunt
Mom: Stacy London
Daughter: Miranda Cosgrove
French Cousin: Audrey Tautou
British Cousin: Catherine Zeta-Jones
Brother 1: Ryan Reynolds
Brother 2: Dane Cook
Mom: Stockard Channing
Daughter: Carey Mulligan
Brother 1: Paul Reubens
Brother 2: Alan Cumming
Brother 3: Emo Philips
Older Brother: Thomas Haden Church
Younger Brother: Steven Mackintosh
Brother 1: Jim Carrey
Brother 2: Stefán Karl Stefánsson
And, if we could time travel:
Brother 1: Kelsey Grammer
Brother 2: Bob Hope
For related hilarity, I recommend http://totallylookslike.icanhascheezburger.com.