This is of the "to puzzle graduate students" variety, but I was taken enough with it to write it up in a short noteshort note:
Let $V$ be a vector space over a field $F$, of dimension at least $2$, and consider coverings $\mathcal{C} = (W_i)$ of $V$ by proper subspaces. Does there exist a countable covering $\mathcal{C}$? (It depends on $\dim V$ and $\# F$, but perhaps not exactly as you expect!)