A musical episode in Enterprise might have been difficult to pull off, no holodecks and all.
Hey, we're talking Star Trek here. You don't need holodecks, even though we've seen one developed by aliens. It could be done as:
1. Warp field imbalance sends them into an alternate universe.
2. Transporter malfunction traps everybody in the pattern buffer for a full hour, as in "Vanishing Point".
3. Weird space anomaly does the same thing as #1.
4. Presented as the feature for Movie Night.