Mild:
* Dull: A common and straightforward alternative.
* Tedious: Implies something that drags on and feels like a chore.
* Monotonous: Highlights a lack of variation or excitement.
* Lame: Often used for jokes or ideas that fall flat.
More colorful:
* Blah: A simple and versatile expression.
* Crappy: More informal and negative, suggesting something of low quality.
* Uninspiring: Conveying a lack of motivation or interest.
* Snoozefest: A playful term for something incredibly boring.
* Drag: Implies something that feels like a burden or takes forever.
* Dead: Can be used to describe a party or atmosphere that lacks energy.
Slang for specific situations:
* Dry: Often used for humor that fails to elicit laughter.
* Cheesy: For something overly sentimental or clichéd.
* Corny: Similar to "cheesy," but more dated.
* Clichéd: For something predictable and lacking originality.
The best slang term to use depends on the context and your audience.