There's no blanket setting for the board but I'll take that into account while I work (slowly) on a Tartan Green Theme (with nautical stuff of course).
In the meanwhile, when you come to the board you can bump up the size of all fonts locally.
If you have IE, and a wheel mouse - hold control and roll the wheel towards you
If you have IE and no wheel mouse - From the menu choose
View -
Text Size - and select one that's comfortable.

Note for Internet Explorer

If you change it, the next window you open will use that setting.
If you have another browser, let me know and I'll investigate.
P.S. If you see a nice font, post the address of the page and I can try to copy it for use in the Tartan theme.