According to the DVD commentary, the women one character is shown having sex with in the store room during a montage were portrayed by porn actresses.
According to the making-of featurette on the DVD release, the man who plays the Middle Eastern bus passenger with the backpack was actually the real-life clerk at the convenience store where part of the movie was filmed. The featurette shows the man being hired on the spot by the director prior to filming the convenience store sequences.
According to the making-of featurette on the DVD, part of the first day's shooting had to be redone as the decision was made to replace the actor originally cast as Mr. Krebbs. It is also mentioned that an unidentified actress, who had been cast as Sherri, turned down the role, requiring last-minute recasting of that part, too.