This is one of those episodes where I really like both entries in the entire half-hour episode.
"Arthur's First Sleepover" is a fun story (I remember the book having a slightly different ending, where apparently D.W. ended up in the paper), and the whole alien scare in town offered a nice little angle for Arthur, Buster, and Brain to be a little nervous about the sleepover (I liked each of their dreams as well)... and of course, D.W. wanting to join in on the fun is very typical little kid stuff... I remember when I was 10, my next door neighbor's little sister (who was half our age) always wanted to tagalong with us and our friends in the neighborhood whenever we'd play (made worse was that she had a crush on me too, lol). It does seem just a LITTLE dated today though, with Arthur wanting to bring a TV in the tent... in this day and age, they'd be wanting to bring their cellphones or tablets or something, lol.
"Arthur's New Year's Eve" is also a very strong and relatable story: when your a kid, one thing you always want to do is stay up late, though you don't always get to (funnily enough, now that I'm grownup and don't have a bedtime, staying up late doesn't feel so special anymore, lol), but especially at New Year's, because you want to see just what exactly happens when the old year ends and the new year begins. Speaking of which, which of the other kids' tales would you like to see? I like each of them, but I think I'd particularly like to see a flash of green light filling the sky as the new year begins, that'd be pretty cool... though I'd imagine an actual wrestling match between an old man and a baby would be hilariously entertaining. The grown-up meeting almost seemed more like a stand-up convention... "I told my kids spinach is good for 'em, but everybody knows we just like to see the funny faces they make when they eat it! Yuck!" Oh, and D.W.'s line about being trapped in a timewarp and never getting any older is priceless... apologies to Joe Fallon and Marc Brown for stealing that joke for one of my videos last year.