You mean just casual conversation? You just need a general starter question; nothing too direct. "How are you this morning?" "What's news?" ("Whassup" is far too slangy; don't use it.) "Did you do anything interesting over the weekend?" (or "...earlier this week?") "How's your week going?" "Any plans for this weekend?" If you know about something they have been doing or working on, you can ask about that.

Hi, how are you today? Did you have a good weekend? Have you got a few minutes to talk? I am learning English and I love the chance to talk with native speakers. How did you get to work today? Did you get wet coming to work in the rain? How do you like working here? I enjoy it quite a lot.. there are some suggestions for you..