Random Topic Generator
I can't tell from your question whether you are wanting ideas to improve this python code or the project itself.  Your code above works and is readable, so take the following re-spelling of it as minor nitpicks.

def topics(f):
    for i in open(f):   # inline the call to open(), and drop the implicit 'r'.
        yield i.strip() # "yield" turns this into a generator function that will only
                        # read as many lines of the file as are requested.

def mainp():  # consider renaming to something more descriptive (generate_topics?)
    wordlist = topics('../data/' + sys.argv[1])
    response = True # Or any "truthy" value that drops us into the while loop one time.
    while response:
        print random.sample(wordlist, int(sys.argv[2]))
        response = raw_input()

if __name__ == "__main__":  # Putting in this if guard allows you to import your 
    mainp()                 # functions above from anywhere else you might want them.


You may want to peruse the HOWTO for generator functions.