Certamen Question Database This is site contains an enormous bank of certamen questions on all aspects of the Latin language and classical civilization. It also contains the source materials for the NJCL Competitive Certamen, study questions for the source materials, and links to purchase the source materials.
http://www.thelatinlibrary.com/certamen/certamenquestions.html Virginia has made available a number of rounds of certamen questions on this site.
http://www.c-e-d-inc.com/ Creative Electronic Design is about the only company which sells certamen machines
Forum Romanum This site covers many aspects of the ancient classical world, including language study, virtual tours of Rome, Roman history/life/culture, and many other interesting glimpses of life in the ancient world.
http://www.users.globalnet.co.uk/~loxias/oldindex.htm The 'Classics Page' has online quizzes on works of classical literature, links to other websites, games, and more.
Demodocus.com This site contains self-tests on all aspects of grammar, vocabulary, and classical civilization. I especially recommend the variety of grammar and vocabulary drills which are offered. With this site, you can easily review basic Latin vocabulary and elementary noun/verb forms.
http://www.stoa.org/~mahoney/teaching/vocab200.html a list of the '200 Essential Latin Words' for translation
http://www.cambridgescp.com/singles/GCSE_voc/GCSE_voc.html how good are you at Latin vocabulary? use the timed drills to test your speed and knowledge. just click on any of the 'vocab testers'
http://www.tabney.com/subjunctivelatin.html scroll down and practice the forms, uses, and translation of the subjunctive mood
http://www.dl.ket.org/latin3/grammar/ filled with paradigms and explanation on points of grammar.
http://www.tarleton.edu/~cguthrie/blankrome.html This is a blank map of the Roman Empire
http://www.dalton.org/groups/rome/RMap.html clickable map of the Roman Empire