The t-shirt that Kate French (Niki Stevens) wears during the Pink Ride has graphic art of the Showtime web series Girltrash! (2007). French would later appear in the film follow-up called Girltrash: All Night Long (2014) along with her The L Word (2005) co-stars Clementine Ford & Rose Rollins (who was also in the web series).
One of the first times on the show, if not the very first, that you see someone taking a selfie (with Niki) on their phone which, at this time, wasn't as common as today.