So two years ago #and three years ago, I received one of those Mr. Beer "Make your own beer at home!" kits. I still have them both, and one of the gifters has finally decided that I need to get off my ass and make the beer (or whatever comes out of those kits).
Is this likely to go horribly wrong? Should I be concerned about the age of the yeast?
IMO, you have two choices:
1) use what you've got. upside: easy, "free", you're ready to go. downside: the beer is going to be less than optimal. the extract is now 2+ years old, you really want your extract - especially liquid extract - to be as fresh as possible. yeast is probably ok, not ideal but ok. hops will be not-so-OK, expect a slightly sweeter beer and little hop aroma/flavor.
2) buy yourself a mr. beer replacement kit (ingredients only). upside: beer will be better. downside: $.
option 1 would be a good practice run. it'll allow you to see what the process is like and you'll end up with something (may or may not be very good). option #2 will greatly increase your chances of making a good beverage.
Are the kits actually a good starting point, or is this just going to be a huge hassle? Also - I have two cats. Are they likely to be attracted to (or repulsed by) the fermenting goop in the basement?
i've never tried any mr. beer beer, but i've read that they can produce good beer. unfortunately the instructions provided are a bit lacking. they emphasize how simple and quick it is to do, they don't want to fill the user's head with subtleties and doubt that would prevent them from buying another kit. so instead of having a "and here's how to get from good to great", they provide the abre minimum. main thing they don't discuss is temperature control. you want to keep the beer in the low 60's if possible. is your basement heated? unheated basements this time of year are just about perfect for fermenting beer.
don't think you'll need to worry about your cats. my bet is they'll take one whiff and get turned off by the smell of CO2 escaping, once fermentation starts.