I consider it to be a 500 star movie, but how about Top Gun? It's not challenging but it's still a fantastic movie. I'm dead serious. The music is great, it's all very well shot, there are some really nive performances, it's an immensly enjoyable movie all around.

Some other ideas
Tower Heist- a surprisngly good comedy with Ben Stiller and Eddie Murphy, possibly the last really good one he was in.

Wolf- half love story half horror about werewolves, all fun with Nicholson turning into a monster.

The Muppets- a surprisingly good, excellent even, return of Kermit and his team. It's funny, with great songs and some really heartwarming scenes. Gets pretty much everything right. The sequel, Muppets Most Wanted is also really good, not so nostalgic and touching, but I think even funnier.

The Magical Legend of the Leprechauns- basically Romeo and Juliet set in Ireland among Leprechauns and fairies. It's all fluff, but I think a lot of fun for everyone who likes fairytales. There's adventure, war, irish music, love and Colm Meany being awesome as the gruff and rarely sober leader of the leprechauns. What's not to love?

Night of the Lepus- giant bloodthirsty mutant rabbits invade America! Yes, I'm serious. If you ever wanted to see the national guard fight giant bunnies, this is the movie for you. It's so ridiculous it really is great fun.

Dr. Goldfoot and the Bikini Machine- Vincent Price as Dr Goldfoot, who invented a machin that creates sexy female androids he sends out to seduce wealthy men! All manner of crazy sheningans follow.

I think those movies are a little better than 2.5 stars...

If you want real 2.5 star movies with a little bit of charm or laughs...

Warning: 2.5 stars for a reason...but...

Joe vs. the Volcano - Has Tom Hanks and Meg Ryan, just not nearly as good...

No Retreat, No Surrender - A teenager learns Kung-Fu from the ghost of a legendary master in Palm tree laden Seattle...in response to being bullied in High School by the high school karate team. With the climactic final fight against an out of control Russian Karate expert who goes out of control in this Karate Kid ripoff...

I gave that negative stars. :P

How do you feel about a little show called Mystery Science Theater 3000?

Card carrying MISTY.

I feel the movies they watch are more like 0 stars.

As for the show itself, hit and miss to be honest.

Perhaps you're thinking romcoms? Well, it's still the season for Love, Actually (I feel like the hate for it is mostly hipsters rejecting the fact that it was actually popular - not all of it is great, no, but there are some very good scenes). If you want something a little more focused on just two people, I'm a sucker for John Cusack so I'd suggest or go back to the source, [url=http://www.imdb.com/title/tt0098258/]Say Anything (if you're under 30 or so, it's probably too old to speak to you at all).

Perhaps you're thinking cheesy kung fu movies? Have you seen Shaolin Soccer? You don't have to like soccer to like it. Or how about Tai Chi Zero? How can you turn away from a movie with the tagline, "A steampunk, kung-fu throwdown"? (Well, it's cheesy, that's how you could.) (EDIT: Oh, I forgot one of the alpha-predator two-star kung fu movies: Ghost Dog. If you haven't heard of it, you should at least take a look at the page. It's...well...it almost defies description)

These aren't challenging movies, and they're not really great movies (though Say Anything *is* iconic), but they're solid two-and-a-half star fare.

I see. Have you heard of Fun in Balloon Land? Where would you place that?

Or by another scale, say Manos is Z-Movie and Plan 9 From Outer Space is a B...

Not my genre, so I can't recommend anything too close, but if you want a bit of sophistication in the dialogs, Albert Brooks maybe a good choice. Broadcast News is my favorite. Maybe his acting can be bit heavy (idiosyncratic) for some people though.

For Jackie Chan film with more overall lighter mood, I would go with Project A I & II, and City Hunter.

Some more recommendation, not sure they match what you're looking for:
A Knight's Tale
Another You
Groundhog Day
Grumpy Old Men
Lost in America
Office Space
Princess Bride

You just put these movies in a two-and-a-half star list? >.>

If you're very quiet, you'll probably hear the peasants coming with pitchforks and torches. Run, while you can.

*gasp* How dare you, sir! Joe vs. the Volcano is a classic!
You are clearly just a flibbertigibbet suffering from a brain cloud! *hrmph* :)

Seriously though, I really do like this movie quite a bit. I agree, well worth a watch.

Lake Placid !

Unfortunately chinese humor does nothing for me, this goes for both Shaolin Soccer and Kung Fu Hustle, as for Tai Chi Zero, the concept is interesting but I can't stand wire-fu.

I haven't watched Serendipity in forever but I remember it being a bit dumb but enjoying it regardless, I don't think I've ever gotten around to watching Say Anything, so I might do that now. I think you might be mistaking movies that are not great but are fun and competent, with terrible movies you like to laugh at.

Hackers
Bend it like Beckham