Inclusion Criteria:

- Patients must have histologically or cytologically confirmed small cell lung cancer;
confirmation will be done at Memorial Sloan-Kettering Cancer Center (MSKCC) or
locally for participating sites

- Patients' disease has relapsed or progressed after one or two prior chemotherapy
regimens, one of which must have been an etoposide-platinum doublet; eligible
patients will be defined as follows:

- "Sensitive" disease: Patients who had one previous line of chemotherapy and
maintained an appropriate response for > 60 days

- "Refractory" disease: Those patients with either no response to first-line
chemotherapy or progression =< 60 days after completing treatment, or
"sensitive" or "refractory" disease in need of third-line therapy (i.e.
completed or failed two previous lines of chemotherapy)

- Eastern Cooperative Oncology Group (ECOG) performance status =< 1 (Karnofsky >= 70%)

- Patients with asymptomatic brain metastases that do not require immediate whole brain
radiation therapy and are on stable doses of steroids are allowed

- Patients must have measurable disease, which is defined as at least one lesion that
can be accurately measured in at least one dimension on a computed tomography (CT)
scan as per RECIST version 1.1; brain metastases can be considered measurable disease
if they meet this criterion

- Absolute neutrophil count >= 1,500/mcL

- Platelets >= 100,000/mcL

- Hemoglobin >= 8.5g/dL

- Total bilirubin =< 1.5 mg/dL X institutional upper limit of normal

- Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase
[SGOT])/alanine aminotransferase (ALT) (serum glutamic pyruvate transaminase [SGPT])
=< 3.0 X institutional upper limit of normal

- Creatinine =< 1.5 X institutional upper limit of normal OR creatinine clearance >= 50
mL/min/1.73 m^2 for patients with creatinine levels >= 1.5 X upper limit of
institutional normal

- The effects of ABT-888 on the developing human fetus are unknown; for this reason and
because other therapeutic agents or modalities used in this trial are known to be
teratogenic, women of child-bearing potential and men must agree to use adequate
contraception (hormonal or barrier method of birth control; abstinence) prior to
study entry and for the duration of study participation; should a woman become
pregnant or suspect she is pregnant while participating in this study, she should
inform her treating physician immediately

- For women of child-bearing potential, negative pregnancy test within 14 days prior to
starting temozolomide and ABT-888

- Ability to understand and the willingness to sign a written informed consent document

- Able to swallow pills

- Patients will not be excluded based on the diagnosis of acquired immune deficiency
syndrome (AIDS); given the increased risk of infection, these patients should have
cluster of differentiation (CD)4 counts above 200 cells/mm^3; patients with AIDS or
human immunodeficiency virus (HIV) not receiving agents with the potential for
pharmacokinetic interactions with ABT-888 may be eligible

Exclusion Criteria:

- Patients who have had chemotherapy or radiotherapy within 3 weeks prior to entering
the study

- Patients who have not recovered from adverse events due to agents administered more
than 3 weeks earlier; toxicities should have resolved to baseline or to within one
grade level of their baseline (not to exceed grade 2)

- Patients who have been administered ABT-888, any other PARP-inhibitor, or
temozolomide

- Patients may not be receiving any other investigational agents

- Patients with leptomeningeal involvement

- Patients with history of seizure

- History of allergic reactions attributed to compounds of similar chemical or biologic
composition to ABT-888 or temozolomide

- Uncontrolled intercurrent illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements

- Pregnant women are excluded from this study because ABT-888 is PARP inhibitor with
the potential for teratogenic or abortifacient effects; because there is an unknown
but potential risk for adverse events in nursing infants secondary to treatment of
the mother with ABT-888, breastfeeding should be discontinued if the mother is
treated with ABT-888; these potential risks also apply to temozolomide

- Patients with either AIDS or HIV on combination antiretroviral therapy are ineligible
because of the potential for pharmacokinetic interactions with ABT-888; in addition,
these patients are at increased risk of lethal infections when treated with
marrow-suppressive therapy

- Patients with a synchronous active malignancy requiring treatment