improvise
     v 1: perform without preparation; "he extemporized a speech at
          the wedding" [syn: {improvize}, {ad-lib}, {extemporize},
           {extemporise}]
     2: manage in a makeshift way; do with whatever is at hand;
        "after the hurricane destroyed our house, we had to
        improvise for weeks" [syn: {extemporize}]
Source: WordNet® 2.0