In addition to Dwija's excellent point about the Temecula Public Library being a good source of free food coupons for the kids, it's worth noting a few of their other services:
a.) Interlibrary Loan. Can't find the book you want? Not sure you want to spend the money to buy it? Queue it up at the library. Go to the website (or a terminal in the actual library) log in with your library card number and PIN, and search. Find the book you want, and place a hold. They'll call or email you when it's in.
b.) Foreign language learning. The library just debuted a new service, Auralog. Click on the "Auralog" button in the lower right hand corner of the web page when you log in, and it will walk you through creating a (separate) login and starting an online foreign language course. They offer Dutch, German, Spanish, French, Italian, and English. At a net price of FREE, it's way cheaper than Rosetta Stone or Berlitz.
c.) Downloadable audio books. Yes, really.
d.) Children's programs. Everything from cookie decorating to kiteflying to storytime. One caveat--at least at the Pauba Road location, these programs go FAST. Be prepared to get there early and wait in line to get an event pass. Yes, really. They are good programs, but best suited to those who are both punctual and have patient children.
e.) Online Renewal. This should, at least in theory, allow you to avoid late fees.
One thing the library does not offer: a forgiving damaged book policy. If your book gets damp, wrinkled, or discolored, be prepared to pay full market value. Both Dwija and I can vouch for this. As an added insult, you will be given the "option" of donating your just-paid-for book to the Friends of the Library so that they can sell it and make a few bucks at the used book store.
Oh, so let me add
e.) The Friends used bookstore. If you're a bibliophile (and why else would you be at the library?) check it out. The hours are not consistent with the library's hours, so you may want to call ahead, but it is definitely worth a stop. The fiction, cooking, and gardening sections are particularly impressive. Kids' books are always worth a look, and do not miss perusing the "vintage" books--all sorts of lovely weird old books can be had here. Bring a checkbook or cash. Ditto if you have to pay off a book or fine at the library itself.
One final note--the library seems to have excellent utilization. Which is good, in that it would be a shame to see and $18M public facility sit unused, but expect a crowded parking lot and lots of people. The facility itself is huge, so indoors it doesn't feel crowded.
So drop by, tell them Erica & Dwija sent you, and ask them to set the air conditioning at something above "glacial"--we're Temeculans, dammit, anything under 85 degrees in summer feels positively bracing and there are resources to conserve, people.