Parkrun host two weekly 5km runs in Milton Keynes; Willen Lake and Linford Wood. Both start every Saturday morning at 9am. Joining Parkrun is completely free, however please make sure to register online first.
Further information about the Willen Lake run can be found here: http://www.parkrun.org.uk/miltonkeynes/.
Further information about the Linford Wood run can be found here: http://www.parkrun.org.uk/linfordwood/.