CrashDown (fansite); IMDb; TV.com; TV Tropes; TWoP; Wikia; Wikipedia
Originally on the WB, then it moved to UPN, but I didn't get to see it till it was in reruns on Sci-Fi Channel. Anyway, this was basically a teen soap opera, except that some of the teens happened to be aliens. There were Max Evans, and his sister Isabel, plus Michael Guerin. Max and Isabel had been adopted by the Evanses, but Michael wasn't; he was the foster child of a total jerk, and eventually got himself emancipated. Anyway, they all lived in Roswell, NM, where their ship had crashed decades earlier, and they remained in incubation pods in a hidden chamber inside a cliff out in the desert, until they emerged from the pods as young children in the early 80s, I guess. They had no memories, but eventually realized they weren't exactly human. They always hid this secret from everyone.
But one day at a local diner called the Crashdown, a girl named Liz Parker was shot. Max had always liked her, so he used his alien powers to save her life, and after that she got mixed up with him and the other aliens. Also Liz's best friend, Maria DeLuca, got mixed up with them, though she really wasn't happy about it at first. A relationship slowly developed between Max and Liz, which everyone else pretty much disapproved of. Liz had a boyfriend named Kyle Valenti, who was the son of Sheriff Jim Valenti. The sheriff's father had investigated aliens decades earlier, and it pretty much cost him his career and his sanity, but Jim Valenti was now investigating the same things, and the alien kids did their best to avoid him, but eventually he became an ally of theirs. Kyle was upset early on about losing Liz, but eventually he became friends with her again, and Max saved his life once, and he found out about the aliens and got mixed up in it all, and became a Buddhist. I swear to God I'm not making any of this up.
Also, Liz and Maria had a friend named Alex who eventually found out about the aliens, and he was interested in Isabel, who also cared about him but wasn't really ready for a relationship with a human. Also, apparently an older alien had been killing people for decades, and the alien kids were interested in finding him. They learned a bit about him from an old Native American who had known him, and called him Nasedo. Eventually they met him, and an alien girl named Tess whom he'd been looking after since she emerged from the incubation pods around the same time as the others had. Max was drawn to her, and eventually they all found out that these four young aliens had been royalty on their homeworld, or rather that they were human/alien hybrids with half the DNA of alien royals, and some of their memories. They'd been sent to live on Earth after a coup that overthrew the royal family. Max was a king, Tess was his wife, Isabel was his sister, who was married to Michael, who was Max's second in command and most trusted advisor. But Isabel had betrayed them all to the enemy, with whom she was in love. Of course, the people these hybrid kids were all based on had different names. I'm still not making any of this up.
Anyway, Tess was the only one of them who really had much interest in their past, the rest were more interested in who they were now. Except maybe Michael. The only thing really keeping him interested in Earth was Maria, with whom he had a bit of a tumultuous relationship, but they really did care about each other. Plus there were enemy aliens who wanted to kill the good guys, and they did manage to kill Nasedo. And at one point Alex died, and there was some speculation that it may have been suicide rather than just an accident, but his friends wouldn't believe that. Liz was certain aliens had killed him or something, and did some investigating. Eventually it turned out Tess had mind-controlled Alex to translate an alien book or something, and when he realized what she'd done, she killed him. Everyone discovered this just as the aliens were about to go back home, but now they wanted nothing to do with her, and stayed behind. Tess went back to her homeworld, although she had Max's baby, and Max wanted to find the kid, but didn't know how.
And in the third season, Isabel was secretly dating this guy named Jesse Ramirez, who worked in her adoptive father's law offices, and eventually they got married, against the wishes of pretty much everyone, and it was quite awhile after that before he found out about the aliens. And, um, all kinds of other stuff happened that I really can't recall very well, but I might as well not mention it anyway. I've already given too much away, I'm afraid....
In any event, it was actually a pretty decent show, though the third season wasn't as good as the first couple. The end was kind of okay, I guess. And did I mention I'm not making any of this up?