I read about this somewhere within the last year, and when I remember to practise it, it’s really cool. Open up Opera (my usual browser) and search Google. Use the space bar as usual to page down the results. When you reach the bottom of the page press the space bar again. It takes you to the next page of results.
Unfortunately Shift Space doesn’t take you back to the preceding page of results, but the Delete key soon takes care of that (as with most other browsers).