The movie “Splinterheads” introduces rapidly-rising improvisational comic Thomas Middleditch as Justin Frost, a twenty-something slacker whose “thing” is that he has no “thing” at all. Then, one summer night, he visits a touring carnival and meets a small time con artist, or “splinterhead” (Rachael Taylor of “Transformers”) who works one of the booths. This gorgeous blonde has more “things” going for her than anyone Justin has ever met: her name is Galaxy; she sports assorted tattoos; she has a ferociously possessive, possibly psychopathic boyfriend with a mohawk (Dean Winters, of HBO’s “Oz”); and she has a fascinating hobby, called “geocaching,” that Justin has never even heard of. This very 21st Century pastime, part treasure hunt, part trek, and pure adventure, involves finding secret “caches” that have been hidden in remote spots with assorted clues guiding the way. Armed with her GPS, Galaxy takes Justin on one of her expeditions, and from that day forward, for him, there is no turning back. Rounding out the unique comic universe of “Splinterheads” is an eclectic ensemble cast including Lea Thompson (“Back To The Future”) as Justin’s overly indulgent mom; Christopher McDonald (“Happy Gilmore”) as the love-struck cop who keeps arresting Justin to get his mom’s attention; Frankie Faison (HBO’s “The Wire”) as the strapping splinterhead who seduces Justin’s amorous aunt; and newcomer Jason Rogel, as Justin’s best friend, a lawn-care professional who likes more than one kind of “grass.”