Mercer Island went through a rather large upgrade from its previous crappy condition. It is now worth checking out. It's about 4X larger, it now features two rails (one larger than the other and both more easily approached from the left although not impossible on the right). It has a fun low "concrete pic-nic table," stairs, ledges, little banks and the same pyramid with the expansion cracks at the bases. It is a very smooth park which flows well.
Now this wasn't planned out real well. It Features a pyramid in the middle of a square slab of slanted concrete. On the high end of the slope there is a wedge to start off of. If you get to much speed though you'll ollie over the whole pyramid and never be able to stop before the grass. There are also a couple of ledges that are well worn and too short.
Don't go too far out of your way to get to this one...at least not until they expand.