Robert,
Exactly where is this happening (mySQL, gradebook, html pages). Also, it could be a browser difficulty with the theme you're using. Does the problem follow you in a different theme in a different browser? Not knowing this, I'm going to drown you in superflous information.
Things that can cause oversized tables (or things that can fix them):
look in the <table> tag to see if height is specifically defined...if it is, the easiest thing you can do is to change it (e.g. if <table .... height="95px"......> change to <table height="14">)
If it's a picture that's being used as the background that's making your table big....resize the picture or delete it
If it's text that's being used, you can change the font size or direction
CSS2 has a style property called :first-line You'd edit styles.php in the theme you're using to include
table:first-line {line-height: 1.2; }
or
table:first-line {font-size: 75%; }
Bad-news...doesn't work in every browser, and it'll affect every table.
You could set all lines to a specific height using CSS1 (that'll work in every browser)
table {line-height: 1.2;}
or
table {font-size: 75%;}
good news -- works in every browser
bad news -- works on every table
Past that, nothing comes to mind at the moment....but let me know a little bit 'bout your situation and maybe I can help some more.
Mark