The Home and School Association has only one fundraiser (Directory sales, at the start of the school year), but each class undertakes several of their own to help defray costs for parties and such. You can participate in your child’s class fundraisers by going to the Class Representatives page (it’s one of the options under the Activities button in the menu header at the top of the site) and clicking on the WSSD page for your child’s year (Class of 2013, etc.). In addition to the class pages maintained by the school district (each class has a teacher rep who helps maintain content), some classes set up Facebook pages to help coordinate fundraising efforts — those links are there, too.
To help you navigate the fundraisers for each grade, Parent Reps will try to inform parents about the (1) reason for the fundraiser, (2) how much money actually needs to be raised, (3) what level of voluntary participation would be ideal for each parent (parents encouraged to buy 7 widgets, etc.), and (4) start/end dates. Ideally, they’ll also tell you what percentage of sales actually goes to class (e.g., class keeps 90% of widget sales, and 10% is kept by ACME Widgets). If for some reason you do not want to participate but also do not want to feel guilty all year, writing a check directly to your class is always a great option, and maximizes the money actually going to the function rather than supporting some company (which sometimes takes a large cut) — just contact your respective Class Rep to see what type of participation (dollars per parent, on average) they envisioned when they planned the fundraiser.