It isn’t easy being green. Two cable channels offer leprechaun movies for very different audiences. The Hallmark Channel celebrates St. Patrick’s Day with “Chasing Leprechauns” (7 p.m.). Lifting a plot from every single Hallmark movie ever made, Adrian Pasdar (“Heroes”) stars as Michael, a harried corporate overachiever sent to a small Irish town where a fetching bar maid (Amy Huberman) and wee green creatures teach him that there’s more to life than spreadsheets and PowerPoint presentations.

The Irish imps in “Leprechaun’s Revenge” (8 p.m., Syfy) aren’t quite so beguiling. In this shocker, a teenage girl unwittingly unleashes a killer leprechaun on an unsuspecting small town. He’s out to kill everybody who might know where his gold has gone missing. To add a ticking clock to this bubbling pot o’ blarney, the girl and her family have only four days to kill the angry emerald runt or die from an ancient curse. It stars Billy Zane (“Titanic”) and William Devane (“24”).

• Turner Classic Movies will dedicate its daytime schedule to classic Hollywood movies from the Golden Age of Irish stereotyping, beginning with “The Key” (5 a.m.).

The best of the lot depart from the lilt, laughter and shamrocks to contend with darker fare. James Cagney stars as an increasingly violent and erratic revolutionary in the 1959 drama “Shake Hands With the Devil” (11:15 a.m.). Spencer Tracy portrays a fading Irish political boss in the 1958 drama “The Last Hurrah” (2:45 p.m.).

Tonight’s other highlights

• The third round of the 2012 NCAA Basketball Tournament (5 p.m., TNT; 6 p.m., TBS; 6:30 p.m., CBS).

• A ghost stuck in the 1970s becomes a new tenant on “Being Human” (8 p.m., BBC America).

• Hugh Grant, David Guetta and Ronnie Corbett appear on “The Graham Norton Show” (9:15 p.m., BBC America).

• Charles Barkley hosts “Saturday Night Live” (10:30 p.m., NBC), featuring musical guest Kelly Clarkson.