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