Tonight is not the final night of the May Sweeps, but it is certainly the most anticipated. “Friends” (7 p.m., NBC) ends a strong season with an hour-long episode. The birth of Rachel and Ross’s child sets the stage for the popular comedy’s ninth and final season.

As “Friends” fans have surely noticed, Ross and Rachel have been acting like a couple for some time now. They bicker all the time, and for the most part, avoid sex. In other words, they might as well be married. The Chandler and Monica relationship, on the other hand, has deteriorated to a sour joke. Their two season-long courtship and engagement almost ruined this comedy, so the writers have almost written their relationship out of the show. Let’s just hope that nobody feels compelled to match up Joey and Phoebe next season.

Unless something changes drastically, “Friends” will become one of those rare series to enter and leave its final season on top. We have already seen former favorites slip away without much fanfare. While “Dharma and Greg” and “Spin City” have not been officially canceled, we probably have seen their final episodes already. Both were barely noticed by audiences. Unless CBS renews “Touched by An Angel,” that series has departed without a trace.

The departures of Drs. Greene, Benton and Ross leaves Carter (Noah Wyle) and Susan Lewis (Sherry Stringfield) as the only remaining doctors from the original 1994 season of “ER” (9 p.m., NBC). Can they handle the pressure? Carter is put to the test on tonight’s eighth season finale when he orders the hospital locked down after two children with smallpox symptoms arrive.

Ending its sophomore season tonight, the forensic drama “CSI” (8 p.m., CBS) has changed viewing habits, and has challenged NBC’s dominance of the evening more than any other show since Thursdays became the Peacock network’s private domain in 1984. It is the logical, no-nonsense deductive reasoning of Dr. Grissom (William Petersen) and his gang that have catapulted “CSI” to the brink of Number One status.

Tonight: Grissom’s team discovers a disfigured corpse with links to the beauty business. A repeat “CSI” (TV-PG) follows at 9 p.m.

Season finales

On back-to-back episodes of “Charmed” (WB) Paige confronts characters from her favorite fairy tale (7 p.m.); an angel offers the sisters a chance to renounce their powers and lead normal lives (8 p.m.).

Jack gets some acting advice from his idol (Cher, as herself) on an hour-long episode of “Will & Grace” (8 p.m., NBC).

Series notes

Eviction number 12 on “Survivor: Marquesas” (7 p.m., CBS) Wrestling on “WWF Smackdown” (7 p.m., UPN).