[steve_barham]

Sure you can. Ctrl-Shift-A, type 'keymap', and you get a handy popup (same size as the 'recent files' switcher available with Ctrl-E) with the defined keymaps ready to use. Few seconds, maximum.

[chris_overseas]

Even quicker: Ctrl+` brings up a quick switch context menu that allows you to instantly switch keymaps, code styles, L&F and colors.