Well, the thing about Funplex is that it used to be really cool.
I went there as a kid all the time, but the area has been in decline. I haven't been back in probably 8 or 9 years. The arcades were fun, but it will probably be nothing better than what you get at a mall. The main selling point was that it was all indoors, a necessity in Houston, with bowling, skating, put put, and laser tag. Check out these reviews,
http://travel.yahoo.com/p-reviews-2744642-prod-travelguide-action-read-ratings_and_reviews-i;_ylt=AnT4owV6M0GYDKug1TFl8JfAFmoL . They basically say it was good when I last went, but crappy now.
D&B is very classy with a nice restaurant, bar, and other entertainment items like poker (with play money), pool, and shuffleboard. The games there are fun but pricey. Plus depending on w
For a little cheaper alternative, check out Jillians. Similar to D&B but a little more family oriented. Still need to be either 18 or 21 to get in without an adult. Along with Jillians, the Marquee Center has some interesting stores to browse. Also a indoor put put place and a big movie theatre.
Try searching for go-karts in houston. There is a former Celebration Station that has become a little ghetto, but still fun. Read reviews out there to see.