Joey's attempt to "prank the prank" makes no sense. He tries to tell the family that there was no tape in the VCR, and that they were really watching the live show. If that were the case, then the lottery would have drawn the same exact numbers two weeks in a row since Joey's "winning" ticket had last weeks numbers on it.
When Danny sits down to join D.J. for tea, her hands are touching the cup, then her arms are suddenly folded.
Jodie Sweetin (Stephanie) actually broke her (left) arm during the taping of Love on the Rocks, but is holding up her right arm as if she broke that one. The intro to the next episode, she is holding up her left arm with a sling.
When Keanu starts to climb the final stretch of the mountain, it cuts to an overhead shot and the floor of the soundstage is visible in the lower left corner.