The biggest one (for Ward 1, where Columbia Heights is) is the at-large Council elections. You vote for two candidates, and Robert White won the Democratic primary and will probably coast to the general election victory. That's a good thing -- he seems like a good candidate and was endorsed by most major news outlets in town. Incumbent independent David Grosso is also running and also seems like a good guy. He was endorsed by a lot of liberal groups.
If you live in Ward 4, there's also an election for council, but incumbent Brandon Todd is running unopposed.
Another important election are the Advisory Neighborhood Commissioners -- these are elected officials who represent a few blocks and serve on a neighborhood committee -- for Columbia Heights there are a total of 24 commissioners in two areas: ANC1A (northern Columbia Heights) and ANC1B (southern Columbia Heights.) Their main duties are to advise the city council about local issues (hence the name) but they also serve another important role: they are able to block or allow liquor licenses and other permitting issues in their districts.
I'll be reaching out to candidates in the competitive ANC districts to interview them, so stay tuned to read more about your race. It's not a well known role but is important in nightlife, development and planning issues. The full list of ANC candidates is here, and here's a map of all the Ward 1 ANCs. Other ward maps are available here.
In addition, there are elections for the school board, the "shadow" congress rep (who mainly advocates, they do not actually serve) and Eleanor Holmes Norton is running for DC's non-voting delegate to Congress again. She should win handily.