Rashida has a split-second appearance walking with Amy in the 2nd promo for Parks and Recreation.
"...so I put in speed bumps"
Clip via Official Site (NBC)
A couple more cast members for the pilot have also been revealed (minor spoilers)
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Rounding out the cast of NBC's highly anticipated Amy Poehler sitcom, Parks and Recreation, is Paul Schneider, sources tell me exclusively. Named one of Variety's "Ten Actors to Watch" in 2007, Schneider -- whom you may remember as Gus in Lars and the Real Girl or as Rachel McAdams' dopey ex Brad in The Family Stone -- will play Mark, a co-worker of Poehler's character, Leslie Knope. The two had a one night stand at some point, and though she's clearly still into him, he's got his eye on Rashida Jones' character, Ann (whose live-in boyfriend will be played by Chris Pratt).
Insiders also tell me that actor Nick Offerman has won the role of Ron, the employees' Parks and Rec superior.
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Info via ZAP2IT