Groovy script that will pull stats on recent games for the specified SummonerID.

lol-recent-games.groovy

import groovyx.net.http.RESTClient
@Grab(group='org.codehaus.groovy.modules.http-builder', module='http-builder', version='0.7.1' )

def API_KEY = "INSERT-API-KEY-HERE"
def SUMMONER_ID = "28450305"

// FULL DOCUMENTATION AT: https://developer.riotgames.com/api/methods
def client = new RESTClient('https://na.api.pvp.net')

def RECENT_GAMES_PATH = "/api/lol/na/v1.3/game/by-summoner/" + SUMMONER_ID + "/recent"

def response = client.get(path:RECENT_GAMES_PATH, query:[api_key:API_KEY])

def games = response.responseData.games

games.each { game ->
    println("${new Date(game.createDate)}: ${game.gameType}/${game.subType} >> ${game.stats.win ? 'WIN':'LOSS'} - "
        + "${game.stats.championsKilled ? game.stats.championsKilled:0}/"
        + "${game.stats.numDeaths ? game.stats.numDeaths:0}/"
        + "${game.stats.assists ? game.stats.assists:0}")
}