I have implemented a brain-dead and half-baked SPARQL endpoint to a subset of LiAM linked data, but there is the disclaimer. Errors will probably happen because of SPARQL syntax errors. Your milage will vary.

Here are a few sample queries:

• Find all triples with RDF Schema labels – PREFIX rdf:<http://www.w3.org/2000/01/rdf-schema#> SELECT * WHERE { ?s rdf:label ?o }
• Find all items with MODS subjects – PREFIX mods:<http://simile.mit.edu/2006/01/ontologies/mods3#> SELECT * WHERE { ?s mods:subject ?o }
• Find every predicate of every triple – SELECT ?p WHERE { ?s ?p ?o }
• Find everything – SELECT * WHERE { ?s ?p ?o }

Source code — sparql.pl — is online.