At the end of the previous episode, Gilmore Girls: Welcome to the Dollhouse, Lorelai said "Oh, that's my pizza" when the doorbell rang, expecting a delivery boy - not her father. At the beginning of this episode, however, when her father has left and Lorelai is talking to Luke on the porch, she says she's ordering a pizza because she's hungry. This would be unnecessary if one were already on the way.
When Emily and Richard discuss giving Rory ''the talk,' Emily claims she walked in on Logan and Rory "very cozy on the couch" and that they "weren't looking for her keys." But in the actual scene, Emily knocks and doesn't come in until Rory and Logan are off the couch and standing to answer the door, and there are curtains on the windows, so there is no way she could have known they were on the couch or looking for her keys.
The goof item below may give away important plot points.
When Rory is telling Logan about her conversation with the minister regarding the gift of her "virtue," she tells him that he (Logan) now has it, implying she lost her virginity to Logan, when she in fact lost it to Dean.