Nehalem, Atom, Sandy Bridge and Core. Conroe, Wolfdale, Clarkedale and Bloomfield. All processor Architecture and process models (I think, anyway), but where do the names come from? Longhorn was the codename for Vista after a bar in a resort (or so Wikipedia leads me to believe anyway).
The Wikipedia page doesn't really explain why Sandy Bridge is named as it is. It does mention that it was originally named Gesher. What is Gesher? Gesher is a Hebrew word (spelled גֶּשֶׁר in the Hebrew letters) that means bridge, and has a Hebrew name as it was designed by Intel's Israeli R&D team.
They then changed it because it is also the name of a political party in Israel (long predating the chip, so I don't know why they didn't think of that before they named it), but as an homage to the original name, basically just translated it into English and prepended Sandy to further differentiate it from the name of the political party.
In general though, the Oregon R&D team has codenames based off of rivers or occasionally towns in the Pacific Northwest (especially Oregon, but sometimes Washington, such as Tukwila), while the Israeli R&D team names it after a river or landmark in Israel.