Sawtooth Trail is open and riding well. The link you can click on get you the basics, but there's more... sooooooo much more. I highly recommend an exploratory day back there.
The Immigrant Trail is also completely open and riding well. Several variations of this trial exist with the blue section on the map (see link) is the most popular and fun.
Although I haven't been out there to ride it yet, The Flume is surely open and free of snow at this point. The previous link is a really good resource for this trail as well as other surrounding goodness. (is goodness really a word??) Note: surrounding goodness probably not rideable yet due to snow.
The Tahoe Rim Trail has stuff open as well. I'd be thinking southern exposure and not getting too high just yet. I'll be doing some serious "research" on this trail over the next few weeks. Check back for the latest / greatest.
Gravity fed types will be happy to know that Northstar's opening day is this weekend!! This place is serious fun. It's not Whistler, but it's right in our back yard. If you're looking for a more "deep woods" adventure, you can't go wrong with Downieville. Shuttles are starting this weekend as well. Get there before the trails get too "haggard".... that's my plan at least.
Wherever you ride: have fun & be safe.