A common exercise for interpreters is to paraphrase a text or lecture, because that's basically what one does in interpreting if you ignore the fact that the result is in a new language. Two other good exercises are condensing, in which you distill the most essential meaning and thus reduce the size of the original text, and expanding, in which you use more words to say the same thing (without adding any new meaning). Condensing isn't that common in practice because in most interpreting situations your goal is to preserve all the meaning, but expanding is a useful tool for buying time.
My last interpreting class was split almost 50-50 among those who found condensing easier than expanding and those who found expanding easier. I myself am firmly in the latter category. Maybe it's because I'm verbose by nature---exacerbated because I'm a fast talker and a speedy typist---or because I'm so perfectionistic and detail-oriented that I find it difficult to constantly judge what is and isn't "essential" when I'm condensing.
Surprisingly, being the mother of a precocious, observant, and demanding 3-year-old gives me many great opportunities to practice these exercises. I frequently condense when I'm asked to read a bedtime story that's longer than I want, but it's difficult and I find myself often just skipping entire sentences instead of paraphrasing larger chunks to make the text flow more naturally. And expanding is a marvelous tool for obfuscation, as I demonstrated tonight while talking to my husband within earshot of my daughter:
"After those individuals in our domicile who are of less than legal age begin their somnolescence*, would you like to ambulate to that location containing dairy products of 31 varieties?" Translation: "Wanna go for a walk to get ice cream after the kids are in bed?" The inquiry floated right past my daughter, whereas the natural version would have yielded insistent cries of "I wanna come too!"
*It turns out that somnolescence isn't actually a word; somnolence was what I should have used. I think I got it from obsolescence, a common term in the software industry.