This is supposed to be the classic small theropod dinosaur from North America, but it turns out that Ornitholestes has been harder to pin down than researchers originally thought. It appears to be more closely related to birds than the allosaur-grade theropod that some thought. While it's not as close to Paraves as say oviraptosaurs, there are a couple features that seem to be "proto-deinonychosaur" in general, including the narrowing and somewhat stiffened distal tail, a sort of incipient "killer claw" on the second toe, and a vertical pubis. I wish more was known of the wrist and pectoral girdle, but for now they are speculations based on where Ornitholestes comes out in phylogenetic studies. Even at this stage of bird evolution Ornitholestes was almost certainly covered in a fur-like feather covering, and quite possibly sported proto-wings on its hands and tail.
Edit: Wow! This may have been the oldest skeletal on DA without an update, as it sat untouched since 2007. Aside from the usual repose and soft-tissue updates, I also tweaked some of the restored elements to bring them more into line with Ornitholestes place on recent cladograms (specifically the wrist and scapula). Mercifully the known skeletal elements held up more than half a decade later.