The simplest RPC call ever in Python:

Server (file xmlrpc.py):
def fibonacci_naive(n):
    if n == 0:
        return 0
    if n == 1:
        return 1
    return fibonacci_naive(n-2) + fibonacci_naive(n-1)

import SimpleXMLRPCServer
server = SimpleXMLRPCServer.SimpleXMLRPCServer(('192.168.0.104', 8000))
server.register_function(fibonacci_naive)
server.serve_forever()
################################################################

$ python xmlrpc.py 

Client:
>>> import xmlrpclib
>>> server = xmlrpclib.ServerProxy('http://192.168.0.104:8000')
>>> print server.fibonacci_naive(10)
55