While the trend today is portable games that can make you smarter -- spawned by the popularity of Nintendo's "Brain Age" titles -- some are designed to turn you into a jackass.

Steve-O, Ryan Dunn and Johnny Knoxville compete in ridiculous events in "Jackass: The Game."

"Jackass: The Game," for the Sony PlayStation Portable, is based on the hit MTV show and two movies, and lets players make jackasses out of themselves with outrageously silly competitions.

Also available this week for the PSP platform is "Dead Head Fred," a new franchise that challenges you to steal others' brains instead of sharpening your own, as with Nintendo's games.

If these kinds of games are up your alley, here's a closer look at each. Both titles are $29.99 and are rated "Mature" for players 17 years of age or older.

'Jackass: The Game'

It's all about silly stunts in "Jackass: The Game."

Not unlike the "Jackass" television show and feature films, this PSP action game lets you choose to be one of their favorite Jackass characters -- such as Steve-O, Ryan Dunn and Johnny Knoxville, each of whom resemble their real-life counterparts -- and compete in ridiculous events.

For example, you can race a shopping cart against an opponent to see which player can reach the finish line first. But you're on top of a skyscraper, so if you don't stop the cart fast enough you'll end up over the edge, plunging to your death.

In a "Dance Dance Revolution"-like rhythm game, you must press the correct button on the PSP at the right time to rack up points. Sounds familiar, right? Well, you're wearing a jock strap and are dancing in a retail store, before the clerk kicks you out.

What about using an umbrella to prevent getting hit with animal dung, sprayed out of a house? You get the idea.

One of the more fun exercises, however, was driving a golf cart through a course, and your goal is to inflict as much damage as you can within the time limit. This involves driving over flags and other property, as well as keeping away from the security personnel who hang onto your cart, affecting its performance. A similar mission has you careening through a suburban area on top of a garbage can, while holding a rope attached to a speeding car. If you slam into parked cars you might break a few bones, but don't worry, you'll get an "abrasion bonus."

While playing through these scenarios, you will unlock additional game features as well as footage from the "Jackass" TV show. Or you can record, save and replay your wildest moments and share them with friends. You can also play against other friends in the same room.

Problem is, not only are these activities dumb, but they're not very challenging, so the novelty wears off fast. That said, fans of the show might enjoy the increasingly insane and asinine stunts.

'Dead Head Fred'

In this unique adventure, you step into the shoes of a private eye, Fred Neuman, who awakens at the beginning of the game to find out he was murdered, but brought back to life with the help of a mad scientist. There's one small catch, however: Neuman's head is missing. In its place is a jar full of fluid and his floating brain.

And so Neuman goes on a mission to solve his own murder and get his head -- and memory -- back from those responsible for his death, namely a deranged mob boss and his mutant henchmen.

To do so, Neuman must use special powers associated with different "heads" he can put on, which are removed from special enemies. (It sounds gruesome, sure, but it's quite comical.) One head gives Neuman extra strength to "head butt" into objects to break them open, while another sucks in fluids -- such as water or gasoline -- until it fills up like a balloon and then releases wherever needed. The game offers nine such heads to find, each with unique abilities. You can also collect money, which is used to buy upgrades for each of the heads.

"Dead Head Fred" is played from a third-person perspective and offers impressive camera controls and visual effects, especially for a hand-held game. The only problem, however, is frequently loading screens which can take away from the fun, but it gets better once Neuman ventures outside for the first time.

This mature game is bizarre, funny and fresh. Kudos to Chapel Hill, North Carolina, developer Vicious Cycle Software for delivering a gratifying portable entertainment experience. E-mail to a friend