As a follow-up to "Futura," I thought you might find it interesting to ponder the implications of another ubiquitous font: Helvetica.
There is an entertaining documentary about this font in the history of typography (available through the local library system). This typeface might look familiar, because of Arial, the primary typeface of Microsoft, a slightly altered version of Helvetica.
Here is a chart, courtesy of Swiss-Miss.com, showing how minutely they differ:
Here is a quiz to see if you can tell them apart.
And one more ... for the most devoted of typography fans.
If you take either of those, post here how you did.