OK, so I missed a day. I needed time off after finishing the paper grading for the semester and ... oh, who am I kidding, I was busy all day with this.
Anyway, Rescue Me. First off, if you're thinking of watching but you missed the first coupla seasons, I think that's easier here than with most series. Sure, you'll miss back story, but the basic idea of the show is easy to grasp: Denis Leary is a miserable piece of shit who wants to do better but can't. (This is a standard character, but in this case the difference is, he's more a piece of shit than he is a guy trying to do better ... despite the title, he is rarely rescued, the show lacks sentimentality almost completely.) He's a good fireman but takes too many chances when his death wish kicks in. The show grew out of 9/11, and the first season in particular had that date in mind ... the idea was that people were starting to move on, firemen didn't get an instant break just because they were firemen (show takes place in NYC), but Leary's character, Tommy Gavin, hadn't moved on yet. The 9/11 angle is less present now.
Oh, and Tommy Gavin has visions, or something, it's never quite clear. He often sees and talks to his dead cousin, another firefighter who died, in Season Two he sometimes talked to Jesus (yes, Jesus), and this year I wouldn't be surprised if his son, who died at the end of Season Two, shows up.
I could give more plot, but really, you can start watching now and catch up later. Be warned, it's a "guy show" ... I think it redeems itself because we're supposed to see the guys as dickheads, not as cool, but it's a guy show nonetheless, with lots of adolescent humor. FWIW, it's also a good show for eye candy in a beefcake kind of way.
As for the Season Three opener, as Tim Goodman noted, they seem to be foregrounding the humor a bit more, but some of the plot threads of the season are already in place. I won't say anything specific, but Tommy's gonna have another Job-like year, it would appear. If you're intrigued, give it a shot ... you should be able to tell fairly quickly if you're gonna like it. I think it's a very good show, but it's also erratic and Tommy Gavin is not a likable character. Plus it lacks the awesome over-the-top punch of its FX stablemate, The Shield. Also, I believe they reshow each week's episode on Sunday nights, so you can catch the season premiere if you want.