Gemcitabine and Docetaxel in Treating Patients With Recurrent Osteosarcoma (Closed to Accrual as of 12/21/06) or Ewing's Sarcoma or Unresectable or Locally Recurrent Chondrosarcoma

DISEASE CHARACTERISTICS: Histologically confirmed* diagnosis of 1 of the following: Recurrent high-grade osteosarcoma (closed to accrual as of 12/21/06) or Ewing's sarcoma Progressive disease after standard therapy Received no more than 2 additional salvage regimens Chondrosarcoma Unresectable OR locally recurrent and unable to be completely resected NOTE: *Biopsy required for isolated pulmonary recurrences Measurable disease At least 1 unidimensionally measurable lesion by medical imaging techniques Ascites, pleural effusions, and bone marrow disease are not considered measurable disease PATIENT CHARACTERISTICS: Age 4 and over Performance status ECOG (Eastern Cooperative Oncology Group) 0-2 (≥ 18 years of age) Karnofsky 50-100% (11-17 years of age) Lansky 50-100% (≤ 10 years of age) Life expectancy Not specified Hematopoietic Absolute neutrophil count ≥ 1,500/mm^3 Platelet count ≥ 100,000/mm^3 (transfusion independent) Hemoglobin ≥ 8.0 g/dL (transfusion allowed) Hepatic Bilirubin ≤ upper limit of normal (ULN) (except for patients with Gilbert's syndrome) ALT ≤ 2.5 times ULN Renal Creatinine clearance or radioisotope glomerular filtration rate > 70 mL/min/1.73 m^2 OR Serum creatinine ≤ ULN for age: Ages 5 and under ≤ 0.8 mg/dL Ages 6 to 10 ≤ 1.0 mg/dL Ages 11 to 15 ≤ 1.2 mg/dL Ages 16 to 18 ≤ 1.5 mg/dL Other Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 3 months after study participation Sensory or motor neuropathy due to prior chemotherapy ≤ grade 1 Sensory or motor neuropathy due to prior surgery or tumor involvement ≤ grade 2 AND stable or improving No active or uncontrolled infection No known hypersensitivity reaction to docetaxel or other polysorbate 80-formulated agents PRIOR CONCURRENT THERAPY: Biologic therapy At least 72 hours since prior filgrastim (G-CSF) No prior allogeneic transplantation No concurrent immunotherapy Chemotherapy At least 2 weeks since prior myelosuppressive therapy At least 6 months since prior myeloablative therapy No prior gemcitabine No prior taxanes No other concurrent chemotherapy Endocrine therapy Concurrent hormonal therapy allowed Radiotherapy At least 6 weeks since prior local radiotherapy At least 4 months since prior extensive radiotherapy to more than 50% of the pelvis At least 4 months since prior cranial spinal radiotherapy At least 6 months since prior total body irradiation No concurrent radiotherapy Surgery No concurrent surgery Other Recovered from all prior therapy No other concurrent investigational anticancer therapy