The details of the formation of the terrestrial planets are long-standing questions in the geological, planetary and astronomical sciences, with the discovery of extrasolar planetary systems placing even greater emphasis on these questions. To date, very little has been done on combining detailed chemical abundance and distribution models with specific planetary formation simulations. Here we present simulations of the bulk compositions of the terrestrial planets and planetesimals in known extrasolar planetary systems. We find that the terrestrial planets produced vary from resembling the planetary composition of the Solar System to being enriched in Ca and Al, Fe or biogenic species such as O, P and C. These enrichments can be taken to the extreme to produce planets unlike anything previously observed.