I've run this event twice now -- the half marathon last year, and the 5K this year. It's one of my favorite local SF events, so I'm sure you'll see me there in the future!
Location: San Francisco, CA, near Golden Gate Park
Date: First Sunday in February (Feb. 6, 2011 this year)
Price: For the half this year, $45 through Jan 7 & $55 after; for the 5K this year, $35 through Jan 7 & $40 after. Huzzah for reasonably priced halfs!!
Deadline: Usually the last Thursday or Friday before the race (Feb. 3 this year)
Sellout Factor: Likely, but usually not until just a couple of weeks before the race
The Expo: No expo, which is just fine with me.
Logistics
Excellent, from my point of view. Close parking can be tough if you don't arrive on the early side, but they do run free shuttles from the Great Highway (where most parking is) to the start and back. The bag check is a little less formal than some of the bigger name races (you get a generic plastic and a Sharpie for scrawling your bib number on it; at the other end, they're lined up on the ground numerically) but has always worked fine for me. Plenty of water and food at the finish, and soft tissue massage if you want it (and are willing to wait; the line definitely gets longer the later you finish). Finally, thankyouthankyouthankyou, Kaiser, for race morning packet pickup. The line was all of four people long for me both years, so as long as you're not cutting it too close to the gun, it's a completely workable option.
The Course
Almost completely flat. There are a few teensy weensy grades as you make your way through the park, but even most of that is downhill. The HM course starts near the east side of the park, loops around the panhandle, heads back through the park, then runs down the Great Highway to Sloat and back to finish just inside the west end of the park. Only a few turns; the vast majority of the course is blessedly straight (or obvious, like looping around the panhandle or the stretch down to Sloat and back). It can get a little breezy on the Great Highway, depending on the weather, but by & large I'd say KP is a fantastic event for a half marathon PR. The 5K course starts at the same time & place as the half & splits off after about half a mile. It's also quite flat with the exception of a brief but steep hill in the first mile. Not what I'd call a breathtakingly stunning course, but reasonably picturesque, and running along the Great Highway is always pretty.
Goodies
For all that I don't have a lot of use for cotton race shirts, I'm a big fan of the longsleeves you get at the KP races. They're high quality, super comfortable, and typically with a design you wouldn't mind wearing in public. I wear both of mine all the time! No medal, but for $45, who needs it?