When the guys are being chased by the bouncer and his father, they are seen speeding away from their hotel (The Riviera) down the strip. But moments later when they stop at a red light, The Riviera can be seen ahead of them.
When the guys from the strip club chase Simon and Marcus to their hotel room, one puts his hand over the eye hole to hide their identities and says "room service". Through the spyhole they see his hand including the fingers. When they then cut to the door you seem him take away his hand which was previously completely covering the spyhole. You wouldn't be able to see any of his hand if he spread his hand completely over the hole.
The phone call between Todd and Simon, in which they talk about the rave and Simon mentions that he knows Claire (who is in the room, as insurance, with Todd), is shown twice. However, they don't coincide with the proper times. When the scene is shown from Todd's perspective, it is night time when he is on the phone with Simon. When the same call is shown from Simon's perspective, it is day time. But Los Angeles and Las Vegas are in the same time zone.
The goof item below may give away important plot points.
When Ronna has the idea to substitute the over-the-counter drugs for the drugs she had to flush, she asks Mannie which ones looked the most like the illicit ones because she knows he "lifted" at least one. On the other hand, she had spilled a bottle of 18 or so, and had to pick up many of these to flush them only an hour or so earlier. Plus she presumably was in a better condition to remember what they looked like than Mannie.