In England a Prakticum would be an internship. Again what is so frustrating is that in one sentence you have to translate Praktikum as a Prakticum and then in the next one the translation is an internship. This is becoming more and more frustrating. If a word has two meanings, both should be accepted. The sentences are isolated ones, out of any context.
A practicum is a course in which theory is put into practice, a practical training or research session. An internship is the position held by an intern, or the period of time when someone is an intern. The "funny" thing is that both internship and practical training are accepted and practicum is omitted as a correct answer. This is inconsistent and self-contradictory.
"apprenticeship" would be better as Lehre -- the sort of education that takes several years to teach you a craft such as blacksmith or mechanic.
Praktikum is usually fairly short (weeks or months, rather than years) and gives you some practical experience but doesn't teach you an entire skill.
Er. I do know that. I meant, in this context. I would imagine someone saying "my internship is fun(n)" - when they are implying that the internship is a joke/not-serious. When using fun as an adjective (hence not capitalized in German) the speaker would mean that their internship is enjoyable/interesting/ exciting. ( A fun(adj) one)