Information about house parties are visible at SLS but you have to become a Sherlock Holms to find them. You'll see in the left-hand column of your home page a link, Events. The menu that appears from this link includes a tab, Parties. The so-called "parties" listed there are not really private house parties but a mile-long list of advertisements for clubs. There is, however, a better category in which to find parties. If you click on the Groups link, another page opens and you will see three categories; Newest Groups, Most Popular, and Closest to Me. Although it is not always evident from the name of the group, many are for house parties. Some of the listed groups are not open for "public" viewing so unless the name of the group points to a profile name, you will not know from whom you should seek an invitation.
One more way to search -- the Groups by Interest area, click on the House Parties link. This one too is loaded with commercial interests as well as single men who are fishing for free sex but actual party groups are here-and-there sandwiched.