I’m home waiting for the installers to show up for my Internet phone service. I’m watching MTV on its 25th anniversary day. Surprisingly, for an institution that usually can’t stop cvelebrating its own self-proclaimed fabulousness, the channel and its Web site are nearly ignoring the birthday.

(MTV’s Web site does offer a selection of ’80s oldies videos, but in an annoyingly Mac-incompatible format. Rival site Fuse has no such discrimination.)

I happened to tune in during a show called The Big Ten, in which the channel reverts, for at least one hour, to its former shtick of playing music videos. (Remember those?) Madonna’s still on the roster there. So are the Red Hot Chili Peppers, Justin Timberlake, Mary J. BLige, Christina Aguilera, Beyonce, Nelly Furtado, Green Day, Beck, the Goo Goo Dolls, Snoop Dogg, and even Mariah Carey. As for the up-n’-comer acts on the show, they fall into definite generic categories. There are corporate-friendly Cobain impersonators, gold-chain-twirlin’ white and black gangstas, bootay-shakin’ soul divas, boys wearing eyeliner, metal-rap-punk fusion confusions. You’ll be comforted, I’m sure, to learn the primary video-imagery cliches still revolve around big cars and small garments.

But, as I’ve sure you’ve heard, MTV’s main fare these days is young-adult “reality” shows. These still include such workhorse concepts as The Real World, Cribs, and Pimp My Ride. There’s also My Super Sweet 16, in which a different rich girl in each episode spends more on her birthday party than you’ll make this year.

MTV’s “remit,” or corporate mission, has always been to own the advertiser-beloved teen and young-adult audience, without spending a lot of money to do so. As this prized audience gravitates further away from TV viewing toward other leisure pursuits, and as better-funded TV ventures take aim at the same target, this task keeps getting harder.

So, like an aging pop star desperate to stay on the charts, its every attempt to prove its continued youth and vitality only shows off how old it’s gotten.