How about Google Glass? In all fairness though, quite a few are only dead as standalone products but have merged into other offerings. Take Google Gears for example - offline storage, worker threads and other APIs for browsers, all of which is now part of regular Chrome.
Glass is still around and under active development, it just isn't a consumer product. It is in use by several enterprises, mostly factories and warehouses.
My read on it is that it was never intended to be a consumer project as soon as they launched it (which explains the lack of polish), but the high level of interest when it was announced convinced them to launch it as one just in case they had stumbled on the next big thing. When that failed to materialize, they dropped it back to a research and enterprise project as was initially intended.
