From baseball in January to Christmas lights on the Washington Monument, 2018 promises Baltimoreans scores of opportunities to have a good time. Some have been around forever (like the Maryland State Fair, a tradition for almost 140 years), while others are relatively new to the cultural landscape (Light City, back for a third edition) or one-offs that may never be repeated (May’s premiere of ”Soul the Stax Musical” at Center Stage). But each one is noteworthy, and festive, and the sort of thing you’d be sorry to have missed. (It would be nice if we could include a Super Bowl parade on this list, but hey, there’s always 2019.) Firm in the belief that all advance planning is good planning, here are a handful of what will assuredly be the best of 2018 — one for each month of the year, plus another half-dozen that deserve your attention.