If you're not in the mood to build your own emulation machine, you can still enjoy a variety of classic games using just your browser. The Historical Software Archive, part of the Internet Archive, has made available a number of older, quality titles including Karateka, Akalabeth and Choplifter.
While the collection is made up mostly of games, you can have a go of WordStar if you want to indulge in the incredible fun of old-school word processing. Alternatively, you can load up Visicalc and experience the dawn of the spreadsheet.
scale=2 at the end of the address and up the number to 3 or 4.