Funny thing about Chicago: St. Paddy’s festivities rarely fall on the appointed day. This year, the O’Revelry begins on Saturday, March 11th, when the river goes green and the stout-emboldened paraders go nuts in the Loop; then the South Side Irish get the last word with their own parade on the 12th. What does this mean? A full 36 hours of observance-and a chance to brace your liver for the actual St. Patrick’s Day (the 17th). Here’s how to do it right.

1 Wake early and get thee to Cleary’s on Clark (3438 N. Clark St.) for an authentic Irish breakfast-because it’s not a morning unless your plate is heaped with sausages, rashers, puddings, beans, and a fried egg.

2 Hop on the 22 Clark bus right outside and get to the Michigan Avenue Bridge by 10:45 a.m. There you’ll see union plumbers dump environmentally safe orange dye into the Chicago River. In a matter of minutes, the Catholic water overtakes the Protestant dye, and the river turns fluorescent green.

3 Hoof it to Buckingham Fountain for the Chicago St. Patrick’s Day Parade, which steps off at noon and proceeds north on Columbus Drive through Grant Park. Impress your friends by telling them that the park’s eponym, Ulysses S. Grant, was a descendant of County Tyrone in Northern Ireland.

4 Warm up afterward at Kitty O’Sheas, a pub inside the Hilton Chicago (720 S. Michigan Ave.), which hosts a Shamrocks for Kids party ($10) to benefit Mercy Home For Boys & Girls. Power down some corned beef, enjoy the Irish music and dance, and drink a few pints. Then have a shot of Jameson’s. Hey, it’s for the kids.

5 Do a jig over to Celtic Crossings (751 N. Clark St.), a warm, genuine pub in River North that, instead of TVs, boasts a singing bartender with a strong voice. You may feel compelled to try to outdo him. If you must, have a Guinness to lubricate your throat. Then, sleep it off, Clancy Brother.

6 Thank God you’re Irish on Sunday, during 9 a.m. Mass at St. Cajetan (2445 W. 112th St.) in Morgan Park. Get there early; it’s crowded. In case it’s been a while for you, that flip-down thingy on the floor is a kneeler, not a footrest.

7 Absolution achieved, head straight to 103rd and Western for the legendary South Side Irish St. Patrick’s Day Parade at noon, an inspiring event begun in 1978 when some kids decided to walk around the block dressed in green.

8 Head north and refuel with a hearty shepherd’s pie at Mrs. Murphy & Sons Irish Bistro (3905 N. Lincoln Ave.). Try to refrain from telling the old joke: “To make shepherd’s pie, do the following: get two shepherds and mince them.” Not funny.

9 If the weather’s nice, hoof it up to Lincoln Square where Danú is playing at the Old Town School of Folk Music (4544 N. Lincoln Ave.). One of Ireland’s best traditional bands, it makes the guy at Celtic Crossings sound like Ethel Merman.

10 Chances are, the band will head to The Grafton (4530 N. Lincoln Ave.), a handsome pub next door, for a few pints and some tunes after the show. Follow them, but keep thy beer goggles in check. After nearly two days of drinking, there’s nothing sexier than a flute player.